In order to explore the evolution law of mechanical property indexes of cement-soil and establish the evolution equation corresponding to each mechanical property index， this paper first analysed the testing data for the mechanical property indexes， such as the shear strength indexes （cohesion c and internal friction angle φ） and modulus （inclduing elastic modulus E， secant modulus E50 and deformation modulus E0） of clay cement-soil in the existing literature； Then， the original sample data of each mechanical property index with cement ratio of 10%~25% and age of 3~90 d was obtained； Next， the mean value and confidence interval with 95% confidence level of the above mechanical property indexes at different ages were estimated based on Bayesian Bootstrap method； Finally， based on the improved interval regression analysis method proposed in this paper， the hyperbolic function equations of the mean value， the upper and lower limits of the confidence interval with 95% confidence level of the above mechanical property indexes were obtained， and the recommended values of the parameters in each evolution equation were given， respectively. The research results can provide a reliable basis for parameter selection in the design and calculation of cement-soil related projects.