The effects of hormone additions at various stages and different basic media, with or without serum, on porcine oocyte maturation in vitro were studied. The results showed that the rate of maturation was not significantly different with three different stages of hormone supplement; the rate of maturation on modified TCM199 medium (54.01%) was higher than that on TCM199 (46.16%) and (47.14%), but these differences were not significant; and the rate of maturation on serum-free medium (67.10%) was significantly higher than that on medium plus serum (52.22%). Therefore, modifed tissue culture medium 199 (mTCM199)+10I U/ml pregnant mare serum gonadotrophin (PMSG)+10I U/ml human chorionic gonadotrophin (hCG)+2.5 IU/ml follicle stimulating hormone (FSH) was a suitable medium for culture of porcine oocytes in vitro, and the rate of maturation was 67.10%.