A new prosauropod dinosaur Xixiposaurus suni gen. et sp. nov. from the lower Lufeng Formation of lower Jurassic in Lufeng of Yunnan, China is reported. The diagnostic characters are as follows: steep slant of the skull roof in lateral view; the maximum height of the mandible larger than twice of minimum height of the dentary; the 4th cervical centrum being longest in cervicals; minimum width of the pubic apron wider of the pubic peduncle; the fourth trochanter having a V-shape notch in lateral view. The phylogenetic analysis shows that it is one of the most derived forms among Chinese prosauropods.