In order to utilize glass powder as a partial replacement of slag to prepare the alkali-activated slag cementitious material, the effect of glass powder content (10%, 20%, 30%, 40%, mass fraction) on the properties of alkali-activated slag-glass powder based (AASG) foamed concrete was studied. The fluidity, compressive strength, drying shrinkage, water absorption, softening coefficient and frost resistance of AASG foamed concrete were tested, and the mechanism was analyzed by scanning electron microscope and X-ray diffractometer. The results show that the use of 10% to 40% glass powder increases the fluidity of AASG foamed concrete by 5.0% to 25.6%. The compressive strength increases first and then decreases with the increase of glass powder content. The 7 d and 28 d compressive strength reach the peak when 20% glass powder is used, increasing by 15.0% and 23.8% compared with the control group respectively. When 20% glass powder is used, the drying shrinkage, water absorption, softening coefficient and frost resistance of AASG foamed concrete are the best. SEM analysis shows that glass powder contributes to the optimization of pore structure and compactness of microstructure. XRD analysis indicates that the main hydration products are C-(N-)A-S-H and hydrotalcite. Therefore, the inclusion of glass powder in AASG foamed concrete as a replacement for slag is feasible, which provides theoretical support for its application in backfill engineering and solid waste utilization.