Zebrafish oocyte maturation was induced by various concentrations of FSH and 17α,20β-DHP. The results indicated that FSH of 1IU/mL and 17α, 20β-DHP of 5ng/mL could initiate significantly germinal vesicle breakdown (GVBD) of zebrafish, separately, while the 17α, 20β-DHP of 5ng/mL had better performance. The analysis of SDS-PDGE and Western blot showed that 17α, 20β-DHP of 5ng/mL activated oocyte MAPK and increased GVBD in the zebrafish. The histochemistry assay showed MAPK was activated at the stages Ⅱ and Ⅲ of oocyte development in the plasm while no MAPK activity was observed at the stage Ⅰ. At the stage Ⅴ, the activated MAPK could be observed both in the plasm and nucleus while GVBD took place. The results indicated that activated MAPK played an important role in promoting the ovary development and began to move from the plasm to the nucleus while it was activated.