Abstract: In this paper , the gr ey corr elat ivity analysis is applied to study on the relationships among fishes in high-yield polyculture pond and analysis of effect of dominant factors on net fish yield .The resul ts are as follows :The relat ion between input of grass carp finger ings and output of siliver car ps is the biggest (R =0 .8242), and the relation between input of bighead carp fingerings and output of gr ass carp is the se cond (R =0 .8075). The input of bighead carp fingerings becomes superiority ma ternal factor , the output of siliver carps becomes superiority junior f actor .