Objective To establish a method for the quality control of Rhizoma Alismatis. Methods The samples of Rhizoma Alismatis were identified with TLC and the content of alisol B-23-acetate in Rhizoma Alismatis was determined by HPLC-ELSD. Results The spots of TLC chromatogram of Rhizoma Alismatis was clear. A good linearity was in the range of 4.4～110.0 ?g/mL of alisol B-23-acetate, r=0.999 2(n=5), and the average recovery rate was 98.98 %(n=9), RSD=1.3 %. Conclusion This method was simple, accurate and with a good reproducibility and can be used for the quality control of Rhizoma Alismatis.