Abstract: In this study, four different maize varieties were used to explore the influence of planting density on the biomass and quality traits. In order to determine the agronomic and quality traits of the tested varieties, five planting densities were designed. The results showed that the optimum planting density of‘Zhengdan 958’ ,‘Fenghe 4’ ,‘Longyu 1’and‘Heisi 1’were 75000 plants/hm², 82000 plants/hm², 82000-90000 plants/hm² and 82000 plants/hm². Under different planting densities, difference of the ear height of the four varieties was not significant, and plant height of three silage maize varieties also had no significant difference. The plant height and ear height of‘Zhengdan 958’were lower than that of the other three silage maize varieties with the same plant density. Quality traits of the four varieties had different responses to corresponding planting density. Correlation between planting density and biomass yield of‘Heisi 1’was negative, while that of the other three varieties were positively correlated. Therefore, in order to achieve high biomass, reasonable plant density should be chosen based on the characteristics of variety.