Abstract: Microcapsules containing carbosulfan with urea-formaldehyde (UF) were prepared by the in situ polymerization method in aqueous medium.The properties of carbosulfan microcapsules were analyzed with emulsifier,rate of pesticide and wall,temperature,acidifying agent,adsorbent agent of formaldehyde,modifier.According to the results,optimum reaction conditions were as follows:emulsion 1602# ∶500#=15 ∶2(m/m),carbosulfan ∶ UF=1 ∶1(m/m),the dosage of emulsifier were 6.0%,5%(NH4)2SO4 as the acidifying agent,1% chitosan as the adsorbent agent of formaldehyde,2% polysiloxane as the modifier.Under these conditions,the microcapsules showed satisfied surface morphology and particle size distribution,with the mean particle diameter of 2.00 μ m,and encapsulating rate was above 90.9%,suspension rate was above 92%.The 20% carbosulfan microcapsule suspension has the characteristics of high stability,and possesses a good potential for its development.