The perfect theoretical calculation models of the spatial balloon’s temperature field and IR radiant feature are built up. The space heat flux which the spatial balloon gets is calculated in the appropriate coordinate system. The surface temperature distribution of the balloon is gotten by solving the transient heat balance equations with the use of the finite element software,ANSYS 10.0. On the basis of the solved surface temperature distribution,taking the balloon as a point object,the spatial distribution of infrared radiation intensity in two IR bands is calculated. Finally,the differences of the surface temperature distribution and the infrared radiation intensity spatial distribution between the spatial balloon gotten in this paper and a spatial ballistic target gotten in our previous work are compared and analyzed in detail. The research results have referential value on infrared detecting and recognition of spatial targets.