In China, maize (Zea mays L.) is the third most important cereal crop, after wheat and rice, and is used as a staple food for humans, livestock and as raw material for many industrial products. The Huang-Huai-Hai Plain is the most important maize production region; however, in recent years, during the maize growing season, especially during the pollination period, extreme weather, such as heat waves and overcast or rainy weather, has frequently occurred in this area. These weather events seriously reduced maize plant biomass and grain yield for the current conventional uniform row spacing pattern, especially with an increased plant density. Crop row spacing can influence the canopy architecture, and optimal row spacing can improve the group structure, increase sunlight penetration, reduce competition between strains, and promote the individual plant growth, which contributes to a high biomass and maize yield. The objective of this study is to further explore the effects of planting patterns combined with plant densities on the photosynthetic characteristics of summer maize. Field experiments involving four planting patterns (three-row strip, four-row strip, five-row strip and the control conventional uniform row spacing pattern)under two plant densities(67500 and 82500 plants/hm²), using the 'Zheng-Dan 958’cultivar were conducted in 2011 and 2012 in this region. Under both high and low plant densities, compared with the control, the strip planting patterns decreased the leaf angle of the 1^st leaf above the ear, and the leaf angles of the 1^st and 2^nd leaves above the ear were smallest under the three-row strip pattern. The SPAD value of ear leaves was significantly influenced by treatments in both years at the flowering stage and in 2012 at the maturity stage. At flowering stage, the SPAD value was increased under strip planting patterns, and the highest and lowest values were observed using the three-strip pattern and the control, respectively. Photosynthesis (Pn), stomatal conductance (Cond), and intercellular CO₂ concentration (Ci) were all significantly affected by the treatments, but the transpiration rate (Tr) was not. Pn was higher in the strip planting patterns than the control, increasing by 51.3%, 37.7%, and 45.7% under the three-, four- and five-row strip treatments, respectively. Among all treatments, the three-strip planting pattern attained the highest Pn, Cond and Tr values. The grain yield was also increased by the changed planting patterns, and the average yields were 16.7%, 6.1% and 10.7% higher in 2011 and 17.2%, 12.1% and 10.6% higher in 2012 under the three-, four- and five-row strip treatments, respectively, compared with the control. At the maturity stage in 2011, no difference in the percentage of barren stalks was observed among the planting patterns, but a significant difference was observed in 2012. The conventional uniform row spacing pattern had the highest percentage of barren stalks in both years. Among all the treatments, the three-row strip planting pattern with a high plant density (82500 plants/hm²) produced the highest grain yield in both years. Thus, the grain yield of summer maize can be mostly enhanced by using a three-row strip planting pattern, especially under a higher plant density.