It was proposed to improve the alkali-activated reaction of red mud through microbial mineralization technology， and the effects of mineralizing microbe amount ，Ca（OH）₂ content and urea concentration on the strength of red mud-activated cementitious materials was investigated. The change of material composition and microscopic morphology of alkali-activated cementitious material under the action of mineralizing microbe were also analyzed by means of scanning electron microscope （ SEM ） and X-ray diffraction （ XRD）， and the mechanism of cementitious material modified by mineralizing microbe was obtained. The results show that microbial mineralization can promote the alkali-activated reaction of red mud to produce more cementitious material and increase the system compactness， thus the strength of red mud-activated cementitious materials is improved. And the strength can increase with increasing the mineralizing microbe amount， the urea concentration， and the curing age. When 1.5 mol/L urea and 75 mL mineralizing microbe after centrifugation are added， the strength of red mud increases most significantly. Compared to the sample with only calcium hydroxide added， the increase in strength can reach 85 .7%. At the same time， the formation of cementitious materials is significantly accelerated by microbial mineralization， which is conducive to the formation of early strength of cementitious materials.