Abstract: In order to explore the controlled release properties of coating- agent, the author carried out pretreatment of the samples referring to the national standard GB/T 8572-2001 and measured N, P, K content in the samples. The initial release rate, differential release rate and cumulative release rate of coated fertilizer nutrients were detected. The results showed that the initial release rates of N, P, K in the coated fertilizer were less than 15%, and the initial release rate of N was greater than that of P and K. Compared to the uncoated fertilizer, the initial release rates of N, P and K of the coated fertilizer were significantly lower, nutrients in the coated fertilizer could release more evenly, and could meet the nutrients demand of crop growing and improve the fertilizer use efficiency. The data proved that the controlled-release fertilizer had good controlled-release properties.