Abstract: In order to study the hydration process of red clay cement grout prepared by red clay in the southwest Wumeng mountain area in southwest China and the micro-morphology of the grout stone, the hydration heat characteristics of red clay cement grout were measured by direct method, and the microstructure characteristics of the hydration products of red clay cement grout were analyzed by scanning electron microscope（ＳＥＭ）, and the effects of cement and structural additives on the hydration products of red clay cement grout were studied. According to the isothermal heat release curve of red clay cement slurry, the hydration process of red clay cement slurry can be divided into acceleration period, deceleration period and stability period, and the slurry hydration kinetics equation was obtained through regression analysis. The SEM pictures of the grout stone of red clay cement grout at different ages can be clearly observed: the skeleton structure at 3 d age was relatively fluffy, forming some small pieces of C-S-H gel; at the age of 7 d, a large amount of C-S-H gel was formed, and the stone body tended to form a whole. At 28 d age, the hydration products of the stone body had basically formed and overlapped with each other to form an overall structure. The research showed that cement is the basis of the hydration reaction for the red clay cement grout. The addition of structural additives improves the hydration reaction speed of cement, thus improves the early strength of grout.