The choices of mussel（Anodonta woodiana）shell width when Chinese bitterling (Rhodeus sinensis) spawn in different shell width groups (50-100 mm) and in mixed shell width groups were studied. The result showed that Chinese bitterling’s spawning rate in groups of shell width less than 50 mm and more than 90 mm were lower than the groups of shell width 50-90 mm significantly. The spawning rate in groups of 60-80 mm were higher than other groups significantly, and the group of 70-80 was the highest. In the same way, the highest spawning rate of shell width was 60-70 mm in study of mixed shell width groups, which was higher than others significantly. The spawning rate declined when the shell width greater than 70 mm or less than 60 mm. The results in both of experiments indicated that Chinese bitterling(weight 1 g) might choose the right mussel, the best shell width of which was 70 mm.