The present invention relates to a polymer emulsion coating agent, a coating controlled-release fertilizer containing said coating agent, and the method for producing the same. The polymer emulsion coating agent of present invention contains alkyd resin prepolymer with neutralization. The present invention also relates to a coating controlled-release fertilizer, which comprises a fertilizer core and a coating applied thereon, wherein said coating comprises the polymer film containing the polymer emulsion coating agent and optionally the inorganic layer containing inorganic powder outside of the polymer film.