Abstract: Effect of chemical fertilizer applied combing with organic manure on yield of rice and nitrogen use efficiency Abstract: four years in site field experiment were conducted to study in the effect of chemical fertilizer applied combing with organic manure on yield of rice and nitrogen use efficiency. The results showed that the sources of nitrogen in soil were mainly come from application. And it was account for above 95% of total nitrogen input. Nitrogen uptake by rice and nitrogen losses via ammonia volatilization was the main pass of nitrogen output. The inorganic nitrogen was easily absorbed by early rice and organic nitrogen was easily absorbed by late rice. Treatment of applied organic manure (M) and chemical fertilizer (NPK) had the same function of increased yield. Applied organic manure increased the soil organic matter and upgrades the soil productivity. The nitrogen use efficiency under the application of organic manure were 37.8% , higher than under the application of chemical fertilizer combing with organic manure (35.1%) and under the application of chemical fertilizer(25.7).