OBJECTIVE： To establish the method for simultaneous determination of 14 kinds of isoflavones in Pueraria radix. METHODS： LC-MS/MS was adopted to detect 14 kinds of isaflavones in 14 batches of P. radix （P. radix：PL-1 to PL-7， P. thomsonii： PT-1 to PT-7）. The determination was performed on Extend C18 with mobile phase consisted of methanol-water （gradient elution） at the flow rate of 0.8 mL/min. The column temperature was set at 22 ℃. The sample size was 5 μL. Ion source was ESI source. The detection mode was negative ion detection. Scanning mode was MRM with jet voltage of －4 500 V； ion source temperature was set at 600 ℃， and atomization gas was 60 psi. The auxiliary gas was 60 psi， collision gas was 7 psi， air curtain gas was 30 psi.  SIMCA 13.0 software wasused for cluster analysis of above batches. RESULTS： The linear range of 14 kinds of isoflavones ranged 10-1 000  ng/mL（puerarin of 10-5 000 ng/mL，r＞0.990 0）. RSDs of precision， stability and reproducibility tests were all lower than 5％. The recoveries were 95％-105％（RSD were 0.8％-4.5％，n＝6）. The total content of isoflavones were different significantly between P. radix and P. thomsonii. The contents of isoflavones in P. radix from different origins were different significantly. Among 14 kinds of isoflavones， the content of puerarin was the highest. Results of cluster analysis showed that 14 batches of P. radix could be clustered into 4 categories， including PL-2 as Ⅰ category， PL-3 and PL-4 as Ⅱ category， PL-5， PL-6 and PL-7 as Ⅲ category， other as Ⅳcategory.  CONCLUSIONS： The method is simple and reproducible. It can be used for content determination of 14 kinds of isoflavones in P. radix and quality control.