A field experiment was carried out to study the influence of combined application of organic and chemical fertilizer under different nitrogen levels on yield in Summer Maize and on nitrogen utilization efficiency. The results showed that: the impact of nitrogen application rate on the directions of nitrogen fertilizers was great. The more of nitrogen application rate, the number of the apparent residue rate, leaching loss and gaseous loss all were increaser. When nitrogen fertilizer rate under the level of 200 kg/hm2, the apparent utilization showed increase, while under the level of 200 kg/hm2, the apparent utilization shows decline. The ratio of organic fertilizer was greater. The rate of apparent utilization and rate of leaching loss was lower, but the apparent residual rate was higher; the rate of gaseous loss was lowest under the condition of combined application of organic manure and chemical fertilizer. The main loss of nitrogen fertilizer was leaching loss. Taking a comprehensive consideration nitrogen among nitrogen application rate and the apparent residue rate and leaching loss, the best nitrogen level was 200 kg/hm2 provided by organic fertilizer and chemical fertilizer with the proportion of 75% and 25% respectively.