Objective：To observe the proliferation of mouse ovarian preantral granulosa cells in order to discuss the reproduction and mechanism of nerve growth factor（NGF） and to establish speedy，sensitive and pollution free detection of cell proliferation with low toxicity. Methods：The mouse ovarian preantral granulosa cells were treated with NGF in vitro and cell proliferation and labeling in－dex（LI） were measured by CCK-8 assay，bromodeoxyuridine（BrdU） labeling and immunocytochemistry staining. Changes in cell cy－cle were analyzed with flow cytometry. Results：Data showed that NGF significantly promoted the proliferation of granulosa cells in a dose-dependent manner. Granulosa cells BrdU positively labeled were visible under light microscope after NGF treatment. Brown positive grains were visible in the nuclei，which indicated that cells were in proliferation period. BrdU LI（％） in the treatment was 40.62%，which was significantly more than that of control（23.57%，P=0.000）. Number of cells and the proliferation index were in－creased in proliferation period and the cell proportion was decreased in G0/G1 phase（P=0.000） after NGF treatment. Conclusions：CCK-8 assay and BrdU labeling are effective，speedy and sensitive in detecting preantral granulosa cell proliferation. The promotion effect of NGF on granulosa cell proliferation might be associated with promotion of DNA synthesis.