In present study,porcine ovaries were obtained and aspirated.Cumulus-oocyte complexes were followed by in vitro culture until the presence of the first polar body(pbⅠ).We investigated the effects of basic culture medium,hormone,follicle diameter,and oocytes wrapped cumulus cells on in vitro maturation of pig oocytes for establishing good in vitro culture system.The results showed that the mature rate of oocytes with mTCM199 was significantly higher than NCSU-23(P＜0.05).Based on the results of experiment 1,the maturation rate of cumulus-oocyte complexes in maturation media with PMSG,hCG and pFF were 55.90%,58.16%,and 51.50%,respectively,showing that the combined treatment group (80.63%) was significantly higher than those of single treatment groups.There were no significant differences in the maturation rates of the ovary follicles larger than 6 mm (76.43%) and 3-6 mm(83.33%) in diameter,but both were significantly higher than the ovary follicles less than 3 mm in diameter(30.94%,P＜0.01).The cumulus-oocyte complexes were divided into level A,B and C according to layer of cumulus cells,which were cultured in vitro matured for 44 h,the maturation rates of level A and B were not significant (P＞0.05),but the both were significantly higher than oocytes of level C (P＜0.01).