When supersonic infrared guided tactical missiles fly, the infrared dome of the missile is affected by the intense aerodynamic heat. The thermal stress generated by heat is the main factor causes thermal cracking of the dome. In response to this problem, in the early development stage of the missile dome, a simple and quick method to select the dome material and whether the next restraint state can be studied is to simulate the actual working state of the solidified missile metal shell of the dome, infrared dome pure thermal stress analysis. The pure heat caused by the temperature gradient .T of the free state dome is separated from the larger heat caused by the superimposed displacement constraint, the smaller pure heat is analyzed separately. The leading factor causing the thermal explosion of the dome is analyzed. Combining the dual-color infrared transmission requirements, taking the zinc sulfide infrared dome as an example, the pure heat simulation is analyzed. The strength limit of ZnS material is greater than pure heat, and the dome can enter the constrained state. In the thermal test the dome did not burst, which proves that this method can be used for the selection of dome materials.