Abstract: Objective：To study the determination method of radix paeoniae alba in xiao′er kang granules by HPLC，improving the quality standard of xiao′er kang granules. Methods：The content of paeoniflorin in radix paeoniae alba of xiao′er kang granules was detected by high performance liquid chromatography(HPLC). Results：Paeoniflorin in radix paeoniae alba had good linear relation ship， the precision，repeatability and recovery rate were good. The solution was stable within 8 h， and the content of paeoniflorin in 3 batches of samples was determined. Conclusion：The improved method is simple and specific，it can effectively control the quality of xiao′er kang granules and improve the quality standards. .