Abstract: Objective To evaluate the influence of the insulin on the development of mouse preimplantation embryo and try to find the IGF-1 express situation in mouse tissues. Method Two-cell mouse embryos, collected from oviduct flushing，were divided into two groups, one group of embryo were cultured for 36 hours in the KSOM media supplemented with insulin at concentration of 0.25 ug/ml as insulin group (Ins group). Another group of embryo was cultured in the same KSOM media but without insulin as control group. After the embryo cultured to blastocysts in vitro, two groups blastocysts were transplanted to the uterine of induced pseudopregnant ICR mouse .The birth weight of the FI fetal mouse were measured. The IGF-1 mRNA express of two group fetal mouse in their three kinds of tissues (liver、muscle and brain) were detected by half-quantities RT-PCR method. Result The rate of Ins-group development to blastocyst after the cultured 36h is higher than that of control group about 9.7%. The average body weight of FI fetal mouse in Ins-group is higher than that of the control group about 17.8% (P＜0.01). Half-quantities RT-PCR results also showed that IGF-1 express level in the muscle of FI Ins-group is higher than that of Control group. But no IGF-1 express difference was found in the liver and brain Conclusions The suitable concentration of insulin in the media supplement in vitro can accelerate the embryo development and increase the IGF-1 mRNA express in muscle of the fetal mouse.