Objective The purpose of this article was to evaluate the influence of cobalt-chromium（Co-Cr） alloy as the material of inner crown on periodontal tissue through detecting the weight of diseased teeth and the concentration of aspartate transaminase（AST） and alkaline phosphatase（ALP） of the gingival crevicular fluid（GCF）after Co-Cr alloy ceramics repairing. Methods In this study, thirty cases of clinical diseased teeth were chosen from thirty patients based on patients’consent. Each tooth conformed to the inclusion criteria. All of the thirty teeth were repaired with Co -Cr alloy ceramics according to the indications. Then GCF of each diseased tooth was collected and weighed at the time of the day before prosthesis, the first and third month after repairing respectively in order to detect the concentration of AST and ALP. Furthermore, comparative analysis for different periods was performed after the data statistics. Results To the weight of GCF and the concentration of AST after the respective comparison of three indexes which was of different periods, numerous of each index increased in accordance with the rule of preoperation, postoperative first month, and postoperative third month（P0.05）, but all the differences had statistical significance in the periods of postoperative third month（P
