OBJECTIVE： To establish the method for simultaneous determination of saikosaponin a and saikosaponin d in Bupleurum chinense water extract， and to optimize its water extraction technology for electromagnetic cracking. METHODS： HPLC method was used. The determination was performed on SB-C18 column with mobile phase consisted of acetonitrile-water （gradient elution） at the flow rate of 1.0 mL/min. The column temperature was 40 ℃. The detection wavelength was set at 210 nm， and  the sample size was 10 μL. Based on single factor experiment， using extraction time， particle size， solide-liquid ratio as factors， total extraction rate of saikosaponin a to saikosaponin d as indexes， the extraction technology was optimized by using Box-Behnken response surface methdology， and compared with the results of ultrasound method and decoction method. RESULTS： The linear range of saikosaponin a and saikosaponin d were 50.70-202.80 μg/mL （r＝0.999 9） and 50.50-202.00 μg/mL （r＝0.999 9）， respectively. The quantitation limits were 0.16 and 0.13 μg/mL， respectively. The detection limits were 0.05 and 0.04 μg/mL，respectively. RSDs of precision， stability and reproducibility tests were all lower than 2％. The average recoveries were 98.23-102.47％ （RSD＝1.80％， n＝6） and 98.84％-102.06％ （RSD＝1.60％， n＝6）. The optimal extraction technology was as follows： the extraction time of 2.50 min； the particle size of 80 mesh， solid-liquid ratio of 1 ∶ 28 （g/mL）. Results of 3 times of validation tests showed that the optimal technology included the average total extraction rates of saikosaponin a and saikosaponin d were 8.42 mg/g， which was higher than that of ultrasonic method （8.34 mg/g） and decoction method （8.06 mg/g）， and the extration time was shorter. CONCLUSIONS： Established method is simple and accurate， and can be used for simultaneous determination of saikosaponin a and saikosaponin d in B. chinense water extract. The optimized water extraction technology for electromagnetic cracking is stable and feasible.