Abstract: The present study was conducted to evaluate the effect of dietary supplementation of ethylcellulose-coated VC on reproductive performance of SPF guinea pig. A total of 24 male and 72 female SPF guinea pigs of reproductive age were included in this study and were randomly divided into 4 groups based on the gender. There were 24 guinea pigs in each group, including 6males and 18 females. The diet of experimental groupⅠ,Ⅱ, Ⅲ was supplemented with 500, 1 000, 1 500 mg/kg of ethylcellulosecoated VC, respectively, and the diet of control group was supplemented with 1 800 mg/kg of monomer VC. The health status of the pregnant female guinea pigs during gestation period and the new born guinea pigs was observed and recorded in two consecutive pregnancies. The pregnancy rate and farrowing rate of female guinea pigs as well as birth weight and weaning rate of new born guinea pigs in the two separate birth orders were calculated and statistically analyzed. The results revealed that the reproduction performance of female guinea pigs in experimental group Ⅰwas similar with that in control group. The reproductive indexes of female guinea pigs in experimental group Ⅱ reached the optimal level, and 1 000 mg/kg of ethylcellulose-coated VC supplemented in diet could meet the demands of the pregnant female SPF guinea pigs for VC. When the supplementation dosage of ethylcellulose-coated VC increased to 1 500 mg/kg, no significant improvement in reproductive indexes was observed. These results suggest the feasibility of replacing monomer VC with ethylcellulose-coated VC as a source of dietary VC, and the supplementation dosage of 1 000 mg/kg is recommended.