This trial was conducted to study the effects of high dietary calcium within short term feeding on muscular calcium content, activity and mRNA expression of μ-calpain of Songliao black swines. Forty-two Songliao black swines with an initial weight of (90.2±2.8) kg were randomly allotted to 8 groups with 6 replicates each and 1 swine in each replicate. The trial lasted for 7 days. The control group was fed basal diets (contained Ca2+ of 0.5%, without CaCl2 and calcium formate), the experimental groups were fed basal diets with 0, 0.5%, 1.0% and 1.5% CaCl2 and calcium formate, respectively. The results showed as follows: compared with control group, CaCl2 and calcium formate increased the content of muscular calcium and activity of μ-calpain (P<0.05), and 1.0% calcium formate group had the best effect; calcium formate could increase the relative expression of μ-calpain mRNA, and the relative expression of μ-calpain mRNA of 1.0% calcium formate group was significantly higher than those of other groups (P<0.05). There was a significant positive relation between muscular calcium and activity of μ-calpain under the treatment of calcium formate after 3 d and 9 d of slaughtering (P<0.05). In conclusion, calcium chloride and calcium formate as the source of calcium in short term feeding of finishing pigs before slaughter could increase the content of muscular calcium and activity of μ-calpain, and the 1.0% calcium formate group had the best effect in this research. ［Chinese Journal of Animal Nutrition, 2009，21(6):960-966］