To investigate the effect of gonadotropin-inhibitory hormone ( GnIH) on the reproductive de-velopment and growth of male mice，30 Kunming mice were divided into 3 groups on average and given30% PVP( Polyvinyl pyrrolidone) -30 dissolved GnIH solution，saline dissolved GnIH solution and thesame amount of saline，respectively． The mice were injected every 5 d and weighed to calculate the feedconsumption rate． At the end of 30 d the experiment，blood samples were collected and testosterone lev-els were measured; testicle quality were measured and testis index was calculated． The results showedthat the administration of exogenous GnIH to male Kunming mice increased the body quality and materialconsumption to a certain extent with no significant difference，and significantly ( P ＜0. 01) decreased thefeed-to-weight ratio． Administration of exogenous GnIH increased testicular quality to some extent andsignificantly ( P ＜0. 05) increased serum testosterone concentration． The test results showed that the ad-ministration of exogenous GnIH could promote the growth of mice，reduce the food intake of mice，reducethe feed-to-weight ratio，and inhibit the development of the reproductive system of mice．