The study was conducted to set up a method for primary culture of ovine preadipocytes, and probe the mechanism of fat deposition in ruminants. Preadipocytes were isolated from perinephrit fat of 1-day-old ovine and cultured by digestive and explanting methods. The morphological changes of cultured cells were observed, growth curve was determined, intracellular fat contents were measured by the method of oil red O staining, and LPL, PPARγ and FAS expression levels were analyzed by real-time PCR. Results showed as follows: primary cultured cells showed homogeneous cell components, vigorous proliferation and high differentiation ratio and presented the morphology characteristics and idiotype genes of preadipocytes. All the results verified their preadipocyte identity. In this paper, a method for primary culture of preadipocytes was successfully set, and the processes of proliferation and differentiation were exhibited in vitro.［Chinese Journal of Animal Nutrition, 2010，22（6）:1768-1774］