Abstract [Ob.jective] This study aimed to examine the effect of different proportions of Wolffia on the growth of Procambarus clarkia in 2 kinds of community scales. [Method] Six proportions of baits mixed by watermeal and commercial feed （0, 20%, 40%, 60%, 80%, and 100%） were designed to feed the Procambarus clarkia juve- niles in 2 community scales to research the growth situation of the crayfish in dif- ferent mixed baits. The growth differences between the minimal community and the larger community of crayfish in the same proportion of Wolffia were compared. [Rr- suit] The growth situations of crayfish in the 2 community scales at different propor- tions of watermeal were as follows： the body length was the longest in 60% water- meal group, and shortest in the pure watermeal group; the regularity was the best in the 20% watermeal group; no matter the minimal community or the larger communi- ty, there was no significant difference in the survival rate between different water- meal proportions. The growth situations of crayfish in the 2 community scales at specific proportion of watermeal were： the average body length of the minimal com- munity was significantly greater than the larger community, and the survival rate also greater than the latter one, but the difference was not significant. [Conclusion] Con- sidering all kinds of index such as growth, survival rate, regularity, the appropriate proportion of the baits mixed by watermeal and commercial feed is 40% to 60%; big community scale has significant inhibition on growth of crayfish, thus, there should be barriers when cultivating Procambarus clarkia juvenile.