Abstract: To research the application effect of coated fertilizer on direct-seeding precocious rapeseed, a field experiment was conducted to investigate the effects of coated fertilizer on carbon and nitrogen metabolism and grain yield of‘Xiangzayou 1613’. The results showed that the metabolism of carbon and nitrogen increased under the application of coated fertilizer, and the content of chlorophyll (SPAD ) increased. In addition, total amounts of soluble sugar and free amino acids were relatively higher but the difference of concentration was not obvious. Moreover, branch number and pods number per plant increased obviously, and seeds number per pod and 1000-grain weight increased slightly. Furthermore, yield of oilseed increased significantly and reached the highest yield of 2066.9 kg/hm2 with the coated fertilizer rate of 1500 kg/hm2. Model fitting results of the production-fertilizer rate indicated that coated fertilizer at the rate of 1611.0 kg/hm2 increased the yields to the highest amount of 2164.9 kg/hm2, with fertilization amount reduced by 13.9% and oilseed yield increased by 13.6% compared with common fertilizer application amount of 1870.5 kg/hm2 and oilseed yield of 1904.8 kg/ hm2.