Abstract: OBJECTIVE To determine the acid value, carbonyl value and peroxidation value of the degree of rancidity in the Chinese medicine Coicis Semen which was for medicine and food dual-use. To compare the differences in the acidity of Coicis Semen under different storage conditions, and establish the quality limit indicators for determination of rancidity of Coicis Semen. METHODS According to the fourth section of the Chinese Pharmacopoeia 2015 edition, the determination of acidity was determined by clustering analysis and empirical discriminant correlation analysis. The limit value of the rancidity of the Coicis Semen was preliminarily determined, and the proposed limit value was verified by 12 batches of qualified pieces. RESULTS The rancidity of the 10 batches of samples tested was quite different, and the degree of rancidity had a certain correlation with the appearance and storage conditions. The proposed limits were verified reasonably and the values were subject to normal distribution. CONCLUSION It is proposed that the acid value must ≤ 30.0, the carbonyl value must ≤ 32.0, and the peroxide value must ≤ 0.035 as the quality limit indicator for the determination of rancidity. This method has high reproducibility and simple operation, and can be used for quality control of Coicis Semen.