The invention relates to a household garbage incineration disposal device, in particular to a household garbage pyrolysis gasifier. A gasifier body comprises an incineration furnace shell, a refractory brick layer and an incineration furnace inner container from exterior to interior. A slag discharging component and a water sealing component are arranged at the bottom of the gasifier body. An air inlet and a combustible gas outlet are formed in the upper portion of the gasifier body. A steam inlet is formed in the bottom of the gasifier body. A steam outlet is formed in the top of the gasifier body. A hollow interlayer is arranged between the refractory brick layer and the incineration furnace inner container. The bottom of the interlayer is communicated with the bottom in the gasifier body. The upper portion of the interlayer is communicated with the combustible gas outlet. An air inlet channel is arranged in the interlayer. The upper portion of the air inlet channel is communicated with the air inlet formed in the upper portion of the gasifier body. The lower portion of the air inlet channel is communicated with the bottom in the gasifier body. Pyrolysis can be carried out on urban garbage to generate combustible gas and slag, the generated combustible gas can be recycled, and the generated slag can serve as building aggregate to be utilized.