In 1991 —1996, It was studied that the relationships of the dry matter accumulation before and after silking stage, leaf area index at silking stage and its component, total kernel number, grain-leaf area ratio, stalk characters, brace root number of population with the formation of high yield in maize. The main indices to the population quality and their regulation for high yield have been proposed to the cultivation. The results were as follows ?.1. The essential indicator for high yield population was high dry matter accumulation during grain filling stage. The relationship between the dry matter accu-mulution at silking stage and the grain yield was y=a+bx+cx~2. The relationship between the dry matter accumulation during grain filling stage and the grain yield was positive. Therefore, the population development before silking should be optimized and the dry matter accumulation during grain filling stage should be increased for high yield.2. The main qualitative indices were for high population photosynthesis at silking stage. The basic indice was optimum LAI such as 5. 10±1.00 for spring corn and 4. 85 ±1. 10 for summer corn with cultivar Yidan No. 13 in Jiangsu production. Consequently, the total kernel number could be used as the indicator to the grain yield and the dry matter accumulation during grain filling stage. The grain-leaf area ratio presanted the well marched level of sink-source relation of popula-