Abstract: Rational close planting is an economical and effective measure to increase crop yield. In order to explore the suitable planting density of major maize cultivars in northern Anhui, we studied the grain number per spike and 1000-grain weight of three major maize cultivars, including‘Zhengdan958’,‘Ludan981’and‘Longping206’. The effects of planting density on yield and correlated characters were further analyzed. The study was performed at agricultural experiment farms of Suzhou Academy of Agricultural Sciences. The planting density was set from 7500 plants/hm² to 30000 plants/hm² with an interval of 7500 plants/hm². Water and fertilizer were supplied sufficiently. High yield cultivation method was also used. Based on the high yield achieved, we analyzed the relationship between crop yield and correlated characters. The results showed that, the planting density had the parabolic relation with the yield of‘Zhengdan958’and‘Longping206’. The most suitable density of compact type cultivar‘Zhengdan958’was 73300 plants/hm². The most suitable density of semi- compact type cultivar‘Longping206’was 68600 plants/hm². The most suitable density of flat type cultivar‘Ludan981’was 45000- 52500 plants/hm². The planting density of compact type cultivar could be increased appropriately. However, it was negatively related to the grain number per spike and 1000- grain weight if the planting density is out of range. So, Ludan981 should be planted in low density to avoid risk.