Canine distemper is one of the most important common viral epidemics in farmed foxes. In this study, the whole blood samples of foxes that had been immunized with canine distemper vaccine were collected from a farming area in Changli County. The antibody against canine distemper virus in the 85 prepared serum samples were detected with a double-antibody sandwich ELtSA method. The results showed among the 85 samples from the 4 farms, 81 samples were antibody-positive, and only 4 samples had no antibody against canine distemper. The overall antibody level was higher in that farming area. It is indicated canine distemper vaccination and vaccination program have gotten attention from most of the local farmers, and the immune effect of canine distemper vaccine is better.