In this paper the effects of mercury chloride on the coefficient of visceral organ of mouse and the meiotic maturation and the fertilization ability of mouse oocyte were studied by in vitro culture and in vitro fertilization (IVF) of mouse oocytes, etc. The results showed that mercury chloride (0.5 and 1.5 mg/kg BW) had obviously toxicity to the liver and the kidney of mouse, and the dose of 1.5 mg/kg BW could damage the ovary function and reduce the number of superovulation oocytes. The results also showed that mercury chloride could inhibit the extruding of the first polar body and affect the quality and the viability of mouse oocyte and reduce the rate of IVF, but little impact on germinal vesicle breakdown (GVBD) of mouse oocyte in vivo. The results indicated that mercury chloride could affect the meiotic maturation of mouse oocyte, obviously block the IVF and injury or make a reduction of reproductive capacity of mouse.