Garbage incinerator

Provided is a garbage incinerator. An upper-layer fire grate and a lower-layer fire grate are arranged in an incinerator body, a primary air inlet is formed in the bottom of the lower-layer fire grate, the inside of the incinerator body is divided into an upper combustion chamber and a lower combustion chamber by the upper-layer fire grate, and the lower combustion chamber is provided with an air door. A top garbage feeding port of the incinerator body is communicated with the upper combustion chamber, and a combustion smoke outlet is formed in the side face and communicated with the upper combustion chamber. A returned smoke temperature rising interlayer is arranged on the side wall of the incinerator body, an annular secondary air inlet is formed in the side wall of the incinerator body and communicated with the lower combustion chamber. The upper-layer fire grate is of an arched structure. The upper-layer fire grate is of an arched structure, so that garbage is not piled in the middle of the inside of the incinerator during falling and is fully combusted, the lower combustion chamber enables the garbage to be continuously and fully combusted under the effect of air fed by the secondary air inlet, and combustion efficiency is greatly improved. In addition, the returned smoke temperature rising interlayer is arranged on the side wall of the incinerator body, smoke returned to the incinerator can be heated to rise temperature, ad energy is saved.