A method for separation and quantitative analysis of Climazone and Butralin 40%EC was described by HPLC,using the Acetonitrile+0.1%phosphoric acid aqueous solution as mobile phase(volume ratio of 80:20),on Agilent ZORBAX SB-C18 4 μm(4.6×150 mm)column and diode array(Dad)detector at 210 nm wavelength.The results showed that the linear correlation coefficient of Climazone and Butralin were 0.9998 and 0.9999,the standard deviation were 0.0725 and 0.0956,the variation coefficients were 0.7090 and 0.3210,and the average recovery were 99.66%and 99.54%.