Abstract: To explore the optimal conditions for the production of high-activity thrombolytic enzymes by Rhizopus chinesis 12 fermented semen sojae praeparatum, the Rhizopus Chinesis 12 was used as fermentation strain, five kinds of beans (black beans, soybeans, red beans, mung beans, white kidney beans) were used as raw materials to screen the best raw materials and pretreatment methods for the processing of semen sojae praeparatum.Using the activity of fibrinolytic enzyme as the indicator, the fermentation process of semen sojae praeparatum was optimized by response surface test, and the product quality was analyzed.The results showed that, the black soybean as raw materials and indicated the optimal formulations as follows:Black soybean after germination treatment for 38 h, inoculation rate was 15% (m/m), fermentation temperature was 31℃, and fermentation time was 7 d. Under these optimal fermentation conditions, the fibrinolytic activity of Semen sojae praeparatum reached to (17122 ±392.7) U/g.Furthermore, the ammonia nitrogen of the prepared semen sojae praeparatum was significantly higher than that of a retail brand (p < 0.05), while, its hardness, elasticity and chewiness were significant lower than those of the retail brand (p < 0.05). In addition, the fibrinolytic enzyme activity of semen sojae praeparatum powder after drying was 16350 U/g, which was significantly higher than that of a certain brand of natto (22%) (p < 0.05).These results indicated that Rhizopus chinesis 12 could significantly increased he fibrinolytic enzyme activity of semen sojae praeparatum (p < 0.05), which would have a great significance for further development of the semen sojae praeparatum with high activity fibrinolytic enzyme.