To understand the effects of sodium nitroprusside (SNP), an NO donor, on the growth and development of porcine preantral follicles in vitro culture, follicles were treated with different concentrations of SNP(0.000, 0.001, 0.010, 0.100, 1.000 mmol/L). Results showed there were no significant variances (P＞0.05) in the follicular diameter between all treatments during in vitro culture; the survival rate in 0.001 mmol/L SNP treatment was significantly higher than that in 1.000 mmol/L SNP treatment(85.28%vs70.60%，P＜0.05); the antrum formation and normal rate of oocyte reached highest in 0.001 mmol/L SNP treatment(79.81%, 50.93%), significantly higher than that in 1.000 mmol/L SNP treatment(79.81vs55.22, 50.93%vs35.00%, P＜0.05); the recovery rate of cumulus cells oocyte complexes (COC) in 0.001 mmol/L SNP treatment was significantly higher than that of control and any other treatments (23.27 vs 15.00 vs 13.89 vs 11.67 vs 8.33, P＜0.05), there were no significant difference between other treatments (P＞0.05); the granulose apoptosis in 1.000 mmol/L SNP treatment was significantly higher than that in other treatments(P＜0.05), while that in 0.001 mmol/L SNP treatment was significantly lower than that in other treatments(P＜0.05), there were no significant differences between other treatments(P＞0.05). Certain SNP was beneficial to the survival, development, antrum formation of preantral follicle and normal development of oocytes, while high level of SNP has toxic effect.