Abstract: 【Objective】The controlled-release formulation of chlorpyrifos microcapsule encapsulated with UF-resin，and its controlled-realease kinetics were studied for optimizing the bioefficacy of chlorpyrifos.【Method】The effects of emulsifier, dispersant, and sodium chloride on encapsulation of microcapsule were investigated by biology photography microscope and photon correlation spectroscopy (PCS)，and the controlled-realease characteristics were studied by gas chromatography.【Result】In the optimal foumulation, the mass weights of Styrene Maleic Anhydride（SMA）as emulsifier and Sodium Polyacrylate（PAAS）as dispersant were 2.5% and 2.0% respectively. And adding sodium chloride of mass weight of 0.4% could improve appearence of microcapsule. The mean diameter of microcapsules was about 10µm，and had good surface shape. The investigation of chlorpyrifos release behavior from microcapsules showed that in early 5 days it was coincided with First-level reaction，its equation was Ln(1- Q) =-0.0835t + 4.5102（R2 ＝0.9820）.The release kinetics in 5-42days was coincided with Zero-level reaction，and followed the equation of Q = 1.6443t + 33.996（R2 ＝0.9927）.【Conclusion】Chlorpyrifos microcapsules of UF-resin displayed good controlled-realease characteristics and satisfied the necessary prerequisites for prolonging control period.