The experiment was carried out with two varieties of corn（ND108 and SY7） to explore the effects of harvest time on yield and quality of different forage maize.The results showed that harvest time was a key factor that influenced the yield and quality of forage maize.Along with the advancement of growth period,dry matter content and fat content increased,while the content of crude protein decreased,neutral detergent fiber and acid detergent fiber content increased first and then decreased.At the same time,biological yield,the nutrient composition yield and total energy increased significantly.As biological yield and the feed quality being considered,SY7 and ND108 should be harvested at 85~90 d,90~95 d,respectively.When two varieties of forage corn were compared,the whole biological yield of SY7 was more than that of ND108,the content of crude protein,crude fiber and total energy of SY7 was better than that of ND108.However,the content of crude fat was less than that of ND108.Considering all of these mentioned above,it was conclude that SY7 was better than ND108.