Abstract: In order to reveal the influence mechanism of straw cover amount and fertilizer amount on the photosynthetic characteristics of maize in the black soil area of Northeast China, three kinds of straw coverage（0.5,1.0 and 1.5 times） and 3 kinds of fertilization（80%, 100% and 120%） and conventional fertilization control CK of 10 treatments were set. The changes of photosynthetic characte-ristics such as Pn, Gs, Ci, chlorophyll SPAD value, and growth indicators such as plant height, yield, as well as components of maize leaves under different straw mulch and fertilizer application amounts were studied and analyzed, and the correlation between growth indicators and photosynthetic characte-ristics parameters and yield under each treatment was analyzed. The optimum straw mulching and fertilization mode was selected by the comprehensive index method. The results show that straw mulching and fertilization can improve the Pn, Gs and chlorophyll SPAD of leaves, and reduce the Ci. Gs increases with straw mulch amount and fertilizer application amount during the whole growth period. Ci increases first and then decreases with the growth period. The overall change trend of chlorophyll is the same as that of Pn, which shows an increasing trend and then a decreasing trend. The maize yield of each treatment increases first and then decreases with the increase of straw mulch amount, and increases with the increase of fertilization amount. Maize yield is 8.9%-21.7% higher than CK treatment except that of the 80% fertilizer treatment group. The comprehensive index method shows that the straw mulch amount of 8 000 kg/hm~2 and the fertilizer amount of 336 kg/hm~2 has the best effect on the growth physiology and yield increase of maize.