Abstract: According to the requirements of heat dissipation for missile-borne active phased array radar seeker, and the characteristics of high ambient temperature, limited structure and weight, high heat flux, high heat consumption, three cooling methods are studied in missile flight stage, including sensible heat consumption of structural parts, latent heat consumption of phase change materials, and self-circulation liquid cooling, and also, air cooling and liquid cooling are studied in ground debugging stage. The results show that the cooling method of the seeker in missile flight stage is about its working duration, which is sensible heat consumption of structural parts for about 1 minute, latent heat consumption of phase change materials for about 5 minutes, self-circulation liquid cooling for 10 or more minutes, and in ground long time debugging stage is air cooling or liquid cooling. Three cooling methods have significant effects on the missile-borne platform, and provide a reasonable reference.