Abstract: A new infrared target detection approach based on principal background suppression is presented.Through analyzing the spatial-temporal correlation of thermal imagery,the principal component analysis technique is utilized to suppress the background clutters.A spatially related fuzzy ART neural network is applied to build the spatial-temporal background models and detect targets by the suppressed frame information.The experiments have been carried out and the results show that the F1 measurement of our proposed approach is up to 94.2%.It is able to suppress background clutters and highlight targets effectively,and it is capable of detecting targets in complex thermal scene accurately.