The present invention provides an infrared image reconstruction method based on block-sparse compressive sensing. The method includes: a block-sparse representation step: representing consecutive infrared small target image sequences as signals having block-sparse characteristics; a temporal correlation modeling step: modeling a temporal correlation of data between the consecutive infrared small target image sequences under a Bayesian framework; and a signal reconstruction and output step: reconstructing infrared small target images using a sparse learning algorithm and outputting final estimates of the signals. The present invention further provides an infrared image reconstruction system based on block-sparse compressive sensing. According to the technical solution provided in the present invention, in the process of reconstruction by compressive sensing, signals are reconstructed using a correlation of consecutive signals in time, such that the reconstruction precision of a single frame of signal can be improved, and the algorithm running time is significantly reduced.