To produce high titre polyclonal antibody (PAb)to the pesticide isoproturon，two compounds named [1-(3-carboxypropyl)-3-(4-isopropylphenyl)-1-methylurea] [HAPTEN 4C] and [1-(5-carboxypentyl)-3-(4-isopropylphenyl)-1-methylurea] [HAPTEN 6C] were synthesized. HAPTEN 6C was conjugated to bovine serum albumin (BSA) with the modified active ester method，and artificial antigen of isoproturon was prepared and then it was as immunizing hapten in rabbits． The anti-isoproturon antibody was obtained．Using HAPTEN 4C as the coating antigen, the method of the indirect competitive ELISA for isoproturon was established and used to determine the titre of the antibody． The antibody had high titre and specificity for isoproturon．