To explore the resource utilization of waste incineration fly ash, the incineration fly ash, coal-fired fly ash, and slag powder produced by fluidized bed incinerator were selected as main raw materials, and alkali-activated bricks were prepared by using sodium hydroxide and sodium silicate as alkali activators. When the ratio of the maximum addition of incineration fly ash was 40%, the 28-day compressive strength reached 28.69 MPa, which meets the requirements of GB/T21144—2007 concrete solid bricks. In terms of environmental compatibility, the HJ/T 300 test on the 28-day alkali-activated brick produced by waste incineration fly ash shows that heavy metals were stable in the brick. Long-term pH-related leaching test reveals that the leaching amount of heavy metal Ba in the brick increased with the decrease of pH value; leaching of heavy metal Zn could be detected in the environment with pH value less than 7, and heavy metals Cd, Cr, Cu, Ni, and Pb only appeared in the environment below pH 6. Results of tank and sink diffusion dissolution test show that the alkali-activated bricks produced by incineration fly ash had an environmentally stable pH value between 11.0 and 11.5 that only heavy metals Ba and Cr appeared, and analysis shows that the leaching amount was trace.