Abstract: The determination method of the active ingredients in tebuconazole and prochloraz 50% micro-emulsion(ME)was established by High Performance Liquid Chromatography(HPLC).Samples were dissolved by methanol and then determined by the reversed phase HPLC.The HPLC conditions were methanol-acetonitrile-water(35∶ 30∶35,by vol)as mobile phase,flow-rate was 1.0 mL·min-1,XTerra RP-18column,Photodiode Array(PDA)detector and detection wave length at 220nm.The external standard method was employed for quantitative analysis.The results showed that the linear relationship between the peak area and concentration was in the range of 101.01to 1 010.08mg·L-1(r=0.999 9)for tebuconazole,and 99.06to 990.85mg·L-1(r=0.999 8)for prochloraz,respectively.Meanwhile,the RSD were 0.19% and 0.13%,and the average recoveries were 101.14 and 101.22%.Our results suggested that the method with simple,rapid and good separating effect,can be used for the quality control and detection of products.