To observe the clinical efficacy of Shexiang Baoxin Pill in the treatment of sick sinus syndrome (SSS) and analyze its mechanism.Methods:From January 2016 to December 2016, 76 patients with SSS were divided into the treatment group and the control group,according to the order of treatment, with 38 cases in each group. The control group was treated with oral anisodamine hydrobromide, and the treatment group was given oral Shexiang Baoxin Pill on the basis of the control group.The treatment last for 8 weeks. Before and after treatment,the average heart rate and esophageal electrophysiology (SACT,SNRT,cSNRT) were measured in 24 hours electrocardiogram and esophageal electrophysiology.And the expression G-395A of Klotho gene was detected by TaqMan fluorescence probe.Results:1) After treatment, the total effective rate of the treatment group(89.47%) was better than that of the control group (73.68%) (P<0.05).2) The average heart rate of the patients in the 24 groups before and after treatment was significantly improved in the two groups(Holter)(P<0.05),and the improvement of the treatment group was significantly better than that of the control group (P<0.05).3) The SACT, SNRT and cSNRT of the treatment group were significantly shorter than those before treatment (P<0.05),and the improvement of the treatment group was better than that of the control group (P<0.05).(4) After treatment,the expression of G-395A in the Klotho gene of the two groups was significantly lower (P<0.05),and the treatment group was significantly lower than the control group(P<0.05).Conclusion:Shexiang Baoxin Pill can effectively improve the clinical symptoms of patients with SSS, and its mechanism may be related to the down-regulation of the expression of G-395A in the Klotho gene.