This paper presented a novel method to detect the signal of the instantaneous infrared target based on the Finite Element Analysis (FEA). The radiation energy produced by flame infrared target was divided to finite element section. Studied the distribution of the unit area energy of flame in the detection system and the calculation method of flame radiation obtained by the photosensitive surface of infrared detector in the optical field, we set up a target detection model based on FEA for infrared targets and deduced a calculation formula of the output signal of the infrared flame detection system. Furthermore, the paper analyzed the factors of the influence detection effect both of the environmental factors and the angle of incidence optical system, and simulated the relationship between all parameters of the established model and the characteristics of the object detected. The results of experimental data was consistent with the simulation result verified the correctness of the infrared target detection model established
