To conduct data mining on prescriptions for dysmenorrhea, find out the association rules between drugs and core prescriptions, and study the experience of contemporary masters of TCM (traditional Chinese medicine) gynecology. Methods:The prescriptions of contemporary masters of TCM gynecology for dysmenorrhea were collected, sorted and entered into weka System to analyze the composition principles through the methods of apriori in weka (support>15％，confidence>0.6)． Results:The study collected 305 prescriptions and 216 medications from 15 doctors to conduct data mining. The study showed that the most frequently used medications were Radix Paeoniae Rubra, Radix Paeoniae Alba, Rhizoma Cyperi, Rhizoma Chuanxiong, and Radix Angelicae Sinensis. The most frequency two-drug-combinations are Radix Angelicae Sinensis-Cortex Cinnamomi, Radix Angelicae Sinensis-Rhizoma Cyperi, Radix Angelicae Sinensis-Fructus Evodiae, Radix AngelicaeSinensis-Rehmannia glutinosa (Gaert.) and Radix Angelicae Sinensis-Rhizoma Chuanxiong. The most frequently used trigeminy medications are Radix Angelicae Sinensis-Rhizoma Chuanxiong-Radix Paeoniae Rubra, Radix Angelicae Sinensis-Rhizoma Chuanxiong-Rhizoma Corydalis, Radix Angelicae Sinensis-Rhizoma Chuanxiong-Radix Glycyrrhizae, Radix Angelicae Sinensis-Rhizoma Chuanxiong-Radix Paeoniae, Alba and Radix Angelicae Sinensis-Rhizoma Chuanxiong-Rhizoma Cyperi. The most frequency tetrageminy medications are Radix Angelicae Sinensis-Rhizoma Chuanxiong-Radix Paeoniae Alba-Radix Glycyrrhizae, Radix Angelicae Sinensis-Rhizoma Chuanxiong-Rhizoma Cyper-Radix Paeoniae Alba and Radix Angelicae Sinensis-Rhizoma Chuanxiong-Rhizoma Cyperi-Rhizoma Corydalis. Conclusion:The most important TCM pathogenesis of dysmenorrhoea is qi stagnation and blood stasis, of which the most important principle of treatment is activating blood circulation to dissipate blood stasis.