Abstract: To study effects of genes on body size and semen quality for white-feather silky chicken and the relation between body size and semen quality ,the body size and semen quality of 44 breeding silky cocks (55-week-old) with single and multiple comb were determined . Results indicate that the average body size of single comb silky cocks is bigger than that of multiple comb ones; the semen quality between single and multiple comb cocks and the correlation between body size and semen quality in single and multiple comb cocks both have no significant difference; the correlation between semen quality and body size in single comb cocks was negative. Besides the significant body size advantage of single comb genes, more attention should be paid to the correlation difference between body size and semen quality of single and multiple comb fowls in breeding.