The alkali activated slag foamed concrete (AASFC) was prepared by chemical foaming method with hydrogen peroxide as foaming agent and water glass as activator. The effects of initial temperature of activator, dosage of catalyst, type of foam stabilizer and pore structure on the basic mechanical properties of AASFC were studied. The results show that by adjusting the initial temperature of activator and the dosage of catalyst, a good balance can be achieved between the gas generation rate and slurry setting and hardening. The AASFC with density of about 250 kg/m3 and good internal structure is successfully prepared by adding appropriate foam stabilizer. Comparing the compressive strength of AASFC prepared with different foam stabilizers at the same density grade, it is found that the performance of AASFC with plant protein as foam stabilizer is the best.