The invention relates to a mixed energy utilization device for an integrated rotary radiant boiler preheating boiler. The device comprises a gasification furnace body and a heat 
recovery device, wherein the gasification furnace body is arranged above the heat 
recovery device; the heat 
recovery device comprises a synthetic gas inlet, a 
radiation heat exchange component, a 
slag bath, a 
convection heat exchange component and a pressure shell; the synthetic gas inlet is positioned on a seal head on the top of the pressure shell; the 
radiation heat exchange component is positioned on the upper part of the 
slag bath; the 
slag bath is positioned on the upper part of 
convection heat exchange component; the 
radiation heat exchange component, the slag bath and the 
convection heat exchange component are positioned in the pressure shell into a whole; a lower slag port of the gasification furnace body is connected with the top of the heat recovery device through a 
flange; and the lower slag port is communicated with the synthetic gas inlet. The 
sensible heat of the gasified coarse synthetic gas can be effectively absorbed, and the generated high-pressure steam or medium-pressure steam is used for power generation or preheating other working media, so that the energy 
utilization rate is greatly improved, and the 
energy recycling efficiency is high; and moreover, the overall size of a 
waste heat boiler is effectively reduced, the device is convenient to manufacture, transport and 
mount, and the dust accumulation problem in the 
convection heat exchange area can be eliminated.