The controlled release period of water-based copolymer-coated urea is relatively short. Using biomimetic modification technology to improve the nutrient controlled release period of water-based copolymer-coated urea and clarify the nutrient release characteristics are important influencing factors for its application in agricultural production. In order to explore the nutrient modification and release mechanism of biomimetic modified water-based copolymer coated urea，this study used water-based copolymer membrane materials synthesized from chitosan，starch and polyvinyl alcohol as raw materials，and nano-silica and 1H，1H，2H，2H-perfluorooctyltriethoxysilane were modified and the biomimetic modified water-based copolymer coated urea was prepared. The kinetic and thermodynamic characteristics of nutrient release of biomimetic modified water-based copolymer coated urea under different temperature and soil moisture circumstances were explained，and its nutrient release was made clear through scanning electron microscopy，energy spectrum analysis，thermal stability analysis，and atomic force electron microscopy mechanism. The test results showed that the sustained release effect of water-based copolymer-coated urea was significantly improved after biomimetic modification，and the cumulative nitrogen release rate in 42 days was 7.23% lower than that of water-based copolymer-coated urea. In addition，the kinetic and thermodynamic release characteristics of the biomimetic modified water-based copolymer coated urea were matched through the first-order kinetic equation. The results showed that the activation energy Ea gradually decreased with the increase of soil moisture content；Gibbs free energy change .G>0，entropy change .S>0，enthalpy change .H<0，which means that the release of coated urea in the soil is not an independent system，but heat exchanges with the soil environment，and it is clear of the relationship between soil temperature，moisture content and nutrient release rate. In addition，the nutrient release mechanism was clarified by means of the structural characteristics of the functional group of the membrane material before and after the biomimetic modification，surface microstructure，surface element changes，and thermogravimetric analysis.