Cdc2 kinase is a catalytic subunit of maturation-promoting factor (MPF), a central factor for inducing themeiotic maturation of oocyte. To understand the role of Cdc2 kinase on the oocyte maturation in crustacean,a complete cDNA sequence of Cdc2 kinase was cloned from Chinese mitten crab Eriocheir sinensis and itsspatial-temporal expression profiles were analyzed during oogenesis at RNA and protein levels. The crabCdc2 cDNA (1364 bp) encodes for a 299 amino acids protein with calculated molecular weight of 34.7 kDa.The Cdc2 mRNAs level showed no significant change in the ovary during oogenesis, whereas higher proteinlevel was found at previtellogenesis, late vitellogenesis and germinal vesicle breakdown (GVBD) stages. Twoforms (35 kDa and 34 kDa) of Cdc2 proteins were simultaneously identified in ovary at all stages.Immunocytochemistry analysis revealed that Cdc2 proteins locate exclusively in ooplasm of previtellogenicoocyte, and then relocate into germinal vesicle at vitellogenesis stage and accumulate on meiotic spindle atoocyte maturation. These findings suggest that Cdc2 kinase has essential roles in inducing GVBD andgenerating meiotic apparatus during the crab oocyte maturation.