The characteristics of the staring infrared temperature measuring technique and the application to measure transient surface temperature distribution of gun barrel were presented. This technique has some merits of quickly, non-contact, high precision and not destroying the temperature field that was measured. The thermo kinetics model of the gun was found. Equation of heat conduct was solved by finite element method. Transient temperature field of surface decided the boundary condition. The transient temperature field of gun was simulated by MATLAB tool box.