OBJECTIVE:To explore the optimal steaming time of Carapax trionycis during cleansing period,and to optimize and improve production technology of Carapax trionycis recorded by current Chinese Pharmacopoeia. METHODS:The mechanical processing replaced the artificial processing method in Chinese Pharmacopoeia. The content of protein and the appearance of Cara-pax trionycis were investigated after steaming for 30,60,90,120,180,240 min during cleansing period. The extract,decoction, ash content,appearance and property of Carapax trionycis decoction piece processed with vinegar were also investigated after cleansed Carapax trionycis decoction piece was processed by sand scalding and vinegar quenching method. RESULTS:The differ-ent steaming time obtained different quality of cleansed Carapax trionycis decoction piece and Carapax trionycis decoction piece pro-cessed with vinegar. Compared with decoction piece steamed for other duration,when the steaming time was 90 min,the content of protein in cleansed Carapax trionycis decoction piece was higher(31.16%),and its appearance was up to the requirement. Cara-pax trionycis decoction piece processed with vinegar had higher contents of extract and decoction(9.13%,11.39%)and lower con-tent of ash(66.29%),and its appearance was up to the requirement. CONCLUSIONS:Different steaming time have certain effect on the quality of cleansed Carapax trionycis and Carapax trionycis processed with vinegar,the optimal steaming time of Carapax tri-onycis is about 90 min during cleansing. The mechanical processing method maybe replace the artificial processing on Carapax tri-onycis for improving its production efficiency.