Total RNA was extracted from soleus muscle, gastrocnemius muscle and extensor digitorum longus in hind leg of the 6-month-old male Bamei, Landrace, and the crossbred pigs (LandracexBamei). The primers of pig FoxO1 were designed and synthesized according to its homologous sequences of human, chimpanzee and rat. The optimal reaction condition and system of PCR was sieved to clone pig FoxO1 gene. Subsequently, the differential expression of FoxO1 mRNA was investigated in different types of skeletal muscle from Bamei, Landrace, and the crossbred pigs by SQ RT-PCR. The expression level of beta-actin was determined as a loading control. The results showed that the expression level of FoxO1 was different in various economic pig breeds and skeletal muscle types. The expression of FoxO1 in skeletal muscle of Bamei and the crossbred pigs was significantly higher than that of Landrace (Plt;0.01). Moreover, the expression of FoxO1 was lowest in soleus muscle, which mainly contains typemuscle fiber, and most abundant in extensor digitorum longus, which mainly contains typeb muscle fiber. This suggests that FoxO1 expression level has the negative correlation with the con-tent of typemuscle fiber. Skeletal muscle development of different economic types of pig breeds may be closely related to the regulation of FoxO1 gene.