Abstract: 【Objective】In view of the serious agricultural pollution and the excessive application of chemical fertilizer in economic crops in China, taking apple production as an example, the optimal amount of fertilizer application for both economic and ecological benefits of apple was estimated.【Methods】The external cost and marginal output of chemical fertilizer were estimated by using dose effect method and secondary production function method.【Results】The results showed that the optimal economic fertilization rate considering ecological benefits was 932.55 kg /hm2, but it was prone to be affected by the change of market price. It would decrease with the increase of fertilizer price and increase with the increase of apple price. The external cost of chemical fertilizer was 0.73 yuan/ kg, and the pollution costs were expensive and ranked as: air pollution < soil pollution < water pollution.【Conclusion】The average fertilization intensity of apple in China meets the requirements of the best fertilization amount, but there are obvious regional fertilization differences in different apple production areas, and the problem of excessive fertilization is more serious in some apple production areas. Therefore, some suggestions such as reducing the financial policy intervention of chemical fertilizer, accelerating the promotion of soil testing formula fertilizer and establishing the ecological compensation system are put forward .