This study focused on the melamine-cyanuric acid crystals formation by melamine does alone, and to explore the resource of cyanuric acid and kidney failure repair. Method The 800ng/ml melamine solution was individually regulated to pH value of 3,4,5, and 6 placed in 37 degrees Cthermostat water bath for acidification which simulated gastric conditions, the reaction time was set at 1,2, and 3 hours, the final solution was dried by nitrogen and tested by GC-MS to analysis the concentration of melamine medicated to cyanuric acid. 78 Wistar male rats of clean grade were randomly divided into the exposure group and control group, 60 rats in exposure group and 18 rats in control group. Melamine was given 25 mg/kg body weight through food in exposure group, 10 rats of exposure group and 3 rats of control group were individually taken for morphological observation after 2 weeks, 3 weeks, 5 weeks exposure, and 2 weeks, 6 weeks, 12 weeks repair after stopped exposure. Results Melamine can be medicated into cyanuric acid under the simulated gastric conditions. The concentration of melamine and cyanuric acid was appeared linear relationship with pH value and reaction time. Melamine exposure led to kidney failure, which melamine-cyanuric acid crystals blockage led to acute kidney injury, and it can be gradually restored without extra treatment after stop exposure. Conclusion Melamine can be medicated under the chemical reaction, kidney failure can gradually restored without treatment, which estimated the melamine decomposition to cyanuic acid under the action of gastric acid was one of the mechanisms leading to kidney injure.