Abstract: The paper aims to investigate the optimal culture condition of sheep preantral follicles and provide evidence to explore the law of sheep follicle growth by studying culture methods. Experiment 1: traditional culture method and agar medium culture method were used to investigate the influence on the growth of sheep preantral follicles; experiment 2: sheep preantral follicles cultured alone and cultured in group were used to investigate the influence of different culture densities on the growth of sheep preantral follicles. The results showed that there was no significant difference between traditional method and agar medium method on the increase of diameter and survival rate after 3 days culture (P >0.05); but after 6 days culture, the increase of diameter and survival rate of preantral follicles cultured by agar medium was extremely and significantly higher than the follicles cultured by traditional method (P <0.01); when cultured by agar medium, during the 6 days, there was no significant difference between follicles cultured alone and follicles cultured in group on the increase of diameter and survival rate (P >0.05). The results confirmed that agar medium culture method was qualified to sheep preantral follicles culturedin vitro ; there was no significant influence of density on sheep preantral follicles culturedin vitro .