ABC's ''World News Tonight'' has taken over as the top-rated network evening newscast, displacing the CBS ''Evening News'' in the most tightly contested continuing ratings race in the television industry.

ABC News's emergence is reflected in a consistent edge in the weekly television ratings and in a growing consensus among network news executives and industry analysts that Peter Jennings has become the most popular news anchor.

Last week, ''World News Tonight'' ranked first for the eighth consecutive week, according to the A. C. Nielsen Company. It tied the CBS ''Evening News'' for the second time in those two months. The NBC ''Nightly News'' was third. The eight-week first-place streak is the longest in ABC's history.

In the last month, ''World News Tonight'' was watched in 10.9 percent of the nation's 92.1 million homes with television sets. The CBS ''Evening News'' was seen in 10.3 percent of the homes, and NBC's ''Nightly News'' was seen in 9.9 percent of the homes. November is one of four quarterly ''sweeps'' periods, when local stations and the networks use ratings to determine advertising rates. In the 1987 and 1988 November sweeps, CBS dominated the evening news broadcasts. A Matter of Money and Prestige

While NBC led the evening news ratings for several weeks in 1986 and 1987, CBS has consistently led the ratings for many years.

While the margin of difference among the three networks is rarely more than one-and-a-half rating points, even a few tenths of a point can mean millions of dollars in advertising revenue. Equally important, the No. 1 position confers prestige on the leading network.

Beginning in 1986, all three networks reduced staff and budgets after changes in their corporate ownership. Ben H. Bagdikian, a professor at the graduate school of journalism at the University of California at Berkeley, said yesterday that ABC had made the best use of its reduced resources.

''The turbulent changes at CBS, especially the Draconian things that were done at the news department, and the same at NBC have clearly had negative effects on CBS and NBC news,'' Mr. Bagdikian said.

News executives at all three networks yesterday emphasized the closeness of the competition in news. But several agreed that ABC had displaced CBS as the network to which the most viewers now turn for news. Even when the CBS ''Evening News'' ranked first nationally, the analysts said, ABC's ''World News Tonight'' was the most popular in the major cities. ABC and NBC news programs also have regularly attracted more viewers between the ages of 18 and 54 - those most attractive to advertisers - than CBS.

The analysts attributed ABC's success to the fact that viewers increasingly preferred watching Mr. Jennings, the ''World News Tonight'' anchor, to Dan Rather of the CBS ''Evening News.'' Another reason for the audience shift, they said, was CBS's failure to raise its prime-time schedule from third place in the ratings while ABC's has closed in on first-place NBC. Oprah Winfrey's talk show, which is shown immediately before local news broadcasts on many stations affiliated with ABC, has also attracted many viewers to those stations' evening news programs, they said. These viewers tend to stay tuned to those stations for network news. Edge in International News

''ABC still dominates in the major markets,'' said Josephine Holz, the director of news audience research for NBC. ''It's true for all their shows, and it's true in news.'' Viewers, she said, told their researchers that ''ABC has a bit of an edge in international news'' and that, given the extraordinary changes in the Soviet Union, China and Eastern Europe in the last few weeks, ''that could be a factor.''

Ms. Holz said that NBC had conducted extensive research on viewer attitudes toward news broadcasts and had found viewers' attitudes to be more positive toward Mr. Jennings than toward Mr. Rather. As an example, she cited what she described as the negative public reaction to Mr. Rather's confrontation with Vice President Bush, in an interview broadcast during the last presidential campaign.

Mr. Rather, who was in Czechoslovakia yesterday, did not return telephone calls by press time.

Mr. Bagdikian said that Mr. Jennings was the winner in a contest of continuing, often unyielding exposure. ''While the manipulation of images has been destructive throughout society,'' he said, ''I think that night after night on television the medium is revealing. While the importance of image is overstressed, I do think that Jennings, from the begining, has given the impression of a serious person who personally knows something about the news.'' 'A Stabilized Situation'

CBS research showed that Mr. Rather had recovered from the incident with Mr. Bush, said David F. Poltrack, CBS's senior vice president for marketing and research. Mr. Poltrack added that the differences in ratings among the three networks' news broadcasts reflected the success of their prime-time schedules and local news programs. ABC News's current dominance is due, Mr. Poltrack said, to ''a stabilized situation for ABC in prime time.''

Roone Arledge, the president of ABC News, acknowledged Mr. Jennings's role in leading ''World News Tonight'' to the No. 1 position. But he added that the division had planned for change long before the corporate takeovers.

''Our hard look was a journalistic one as much as a financial one, and out of that we made ourselves stronger,'' Mr. Arledge said. ''There's a lot of depth there, and over the long haul that's how you win credibility.''

photo of Peter Jennings (ABC)