Abstract: According to the requirement of fully mechanical development of maize planting, a fully mechanical inter-cropping pattern between summer maize and mungbean was innovatively designed and fully discussed to increase the yield and benefits. The theoretical basis will be provided for the modern efficient agriculture planting pattern by this research. The results showed that there was a positive relationship between the yield growing and density increasing of the summer maize as its thousand-seed weight and kernel number decreasing in this inter-cropping pattern; the yield of mungbean had no significant differences between different densities. The density of maize was the main factor which significantly affected the economical efficiency of intercropping crops. Compared to the mono-cropping, the inter-cropping of maize and mungbean increased not only the net output, but also the efficiency of land utilization. The author identified two combinations which had the highest net output, they were 75000 plants maize with 90000 plants mungbean and 75000 plants maize with105000 plants mungbean per hectare.