A temperature field numerical analysis model for the computation of the tank power compartment board is set up.The numerical value of infrared radiation feature of the tank power compartment board is calculated in theory.And radiation spectrum intensity direction distribution has been acquired.The relative error of the calculating values is less than 15.6%,and can basically meet the requirement of engineering applications.The study result indicates that the top board of power compartment is the mainly source of radiation.Exhaust shutter and top board about exhaust pipe is the evidence region of IR radiation character of tank.The infrared radiation of tank power compartment board is mainly 8~12μm bands.