It is widely concerned in terms of the safety risk of using coating materials of slow-release fertilizers because China has leapt to the world’s forefront for the output and consumption in recent years.By introducing the current application of coating materials and analyzing their safety risks including the safety of materials，the degradability of synthetic polymers and the impact of coating materials residue and accumulation on the soil ecological environment，the paper makes a systematic study of the environmental impact evaluation methods and standard indexes of the biodegradability and the eco-toxicity for coated materials.And the grade classification of safety risk for coating materials is proposed，in order to provide technical methods for the scientific evaluation of coating materials and rational use of slow-release fertilizers，and to reduce the impact and risk of using coating materials on food and eco-environment.