Abstract: The production process of metakaolin slag geopolymers realizes the green transformation from industrial solid waste to high-performance materials, and significantly reduces carbon emissions and energy consumption. However, the mechanical properties of this material are highly sensitive to the hydration environment, and its strength fluctuation is directly related to engineering safety and application scope. Therefore, in order to investigate the effects of temperature, humidity and pH value on the compressive strength of metakaolin-slag geopolymers, SEM-EDS, TG, FT-IR and MIP analysis were used to reveal the relationship between the changes in microstructure, gel composition and pore structure and the strength evolution. The results show that high temperature has a significant effect on the early strength of the material. While the hydration rate is accelerated at 60℃, the pore structure is more dense. With the extension of curing age, the optimization effect of high temperature on the strength of the geopolymer is gradually weakened. The appropriate humidity (70%) promotes hydration and inhibits alkali precipitation at the same time, the excitation effect of raw materials is improved, the polycondensation reaction is fully carried out, and the gel content is increased, the structural compactness is improved, the proportion of large pores is reduced to 13%, and the strength can reach 60MPa at 28 days. The high alkaline environment (pH=13) promotes the dissolution and polycondensation of metakaolin and slag particles by inhibiting the diffusion of free alkali, and then the n(Na)/n(Al) value in the hydration products increases, and the N‒A‒S‒H gel content increases significantly, making the structure more dense, with the proportion of transition and gel pores as high as 84%, and the final strength reaches 65MPa at 28 days.