A simple and sensitive analytical method based on RP-HPLC with UV detector$(225{cal}nm)$ and mobile phases using $0.1{\%}$ phosphoric acid and acetonitrile was developed for simultaneous determination of quinclorac, bentazone, 2,4-D, bensulfuron-methyl, dymuron, capropamide, pencycuron, ethofenprox. This method was resulted in recovery of $78{~}96{\%}$ with RSD $3.3{~}7.5{\%}$, LODs $0.12{~}0.84$ and LOQs $0.34{~}1.20{cal}mg/L$. Calibration curves were linear with r of $0.9995{~}0.9999$.