A method for rapid determination of pyrazon content in Herbicide suspended emulsions was developed by RP-HPLC.That is: SHIMADZU 10-A VP Plus HPLC,Sweden Kromasil 100-5-C18 stainless steel HPLC column,mobile phase: methanol + water solution（40:60,by volume）;flow rate: 1.0 mL/min;column temperature: room temperature（temperature changes during experiment process is less than 2 ℃）;detection wavelength: 286 nm;injection volume 20 μL.Results showed that a good linear relationship when pyrazon at 1-100 mg/L,the average recovery was 100.52%,RSD was 0.298%.This method can be used for determine pyrazon content in suspended emulsions with the characteristics of fast,simple and accurate,precise,novel means.