This study deals with the case of multiple internal heat source inversion problem of steady-state based on nondestructive infrared detection. We construct homogeneous and heterogeneous steady heat conduction models of different shapes. Neither the number of heat sources, nor their locations, nor their sizes nor their intensities are known. We use the finite element method(FEM) based on numerical algorithm to analyze the two-dimensional model discretely.The internal heat conduction process of model is analyz...