To investigate the effects of phosphate($P_2O_5$) fertilization levels on the dry matter(DM) yield, nutrition yield, and $P_2O_5$ efficiency of forages in mixed sward of alfalfa-grasses, a field experiment arranged by randomized complete block design with five treatments(0, 50, 100, 150 and 200kg $P_2O_5$/ha) was conducted at Livestock Experiment Station in Suwon, September, 1990 to Feb~ary, 1993. During two years, average DM yields of forages increased as $P_2O_5$ fertilization level was increased, but no significant difference was found between DM 10,754kg of $P_2O_5$ 150kg/ha and DM 10,845kg of $P_2O_5$ 200kg/ha. Cmde protein and energy productivity of forages increased as $P_2O_5$ fertilization level was increased, and the increasing degree was highest between $P_2O_5$ l00kg and 150kg/ha feriilization. With increasing $P_2O_5$ fertilization, mineral contents tended to increase in P, K and WCa+ Mg equivalent ratio, but not to be regular in the other elements. Efficiency of $P_2O_5$ was highest at $P_2O_5$ 150kg/ha fertilization, which produced DM 12.8kg. net energy lactation 75.4MJ. starch equivalent 6.lkStE, and total digestible nutrients 8.6kg per Ikg $P_2O_5$.