The early stability behaviors with time-varying of various foams in alkaline environment and alkali-activated foamed concrete were studied. The results show that compared with plant foam agent and animal protein foam agent， compound foam agent has better stability in alkaline environment. With the increase of alkali activator modulus and alkali equivalent， the settlement distance increases gradually， and the settlement time of alkali-activated foamed concrete shortens gradually， the settlement rate accelerates rapidly. The early stability of alkali-activated foamed concrete is determined by the synergistic effect of foam stability and alkali-activated concrete paste. Under the condition of activator modulus of 1.0， alkali equivalent of 3%， mass ratio of slag to fly ash of 8 to 2 and compound foam agent， alkali-activated foamed concrete with favorable early stability can be prepared.