One of the most important problems of stealth technology is to evaluate the infrared radiation (IR) level received by IR sensors from fighters to be detected. This article presents a synthetic method for calculating the IR emitted from aircraft-skin. By reckoning the aerodynamic heating and hot engine casing to be the main heat sources of the exposed aircraft-skin, a numerical model of skin temperature distribution is established through computational fluid dynamics (CFD) technique. Based on it, an infrared signature model for solving the complex geometry and structure of a fighter is proposed with the reverse Monte Carlo (RMC) method. Finally, by way of determining the IR intensity from aircraft-skin, the aircraft components that emit the most IR can be identified; and the cooling effects of the main aircraft components on IR intensity are investigated. It is found that reduction by 10 K in the skin temperature of head, vertical stabilizers and wings could lead to decline of more than 8% of the IR intensity on the aircraft-skin in front view while at the broadside of the aircraft, the drops in IR intensity could attain under 8%. The results provide useful reference in designing stealthy aircraft.