Taking the envelope layer of controlled-release fertilizer as the control layer 1 of nutrient release, and then assuming that there is a control layer 2 of nutrient release at the junction of fertilizer and soil moisture, Fick’s law is used, combined with the modified mass transfer double membrane theory and liquid film life function, an interphase mass transfer model of nutrient release of envelope-type controlled-release fertilizer is established in spherical coordinates. The Laplace transform method is used to solve the mass transfer partial differential equation system of the model, and the Laplace transform is combined with the liquid film life function, and the expression of the nutrient release rate is obtained without the inverse Laplace transform, so as to provide a method to solve the mass transfer rate in the controlled release fertilizer provided by spherical coordinates at the same time as the theoretical basis of the nutrient transport process of the material.