In this paper, the method of sparse sampling and compressed sensing imaging for forward-looking array SAR is proposed. It is shown that the number of the scatterers in the altitude direction is finite for every observation scene, but the sparse sampling method is designed along the along-track direction in this paper, which is proved to be effective for forward-looking array SAR. Meanwhile, the compressed sensing imaging method is presented to reconstruct the 3D image using the sparse sampling data. The results of simulation experiments validate the effectivity furtherly.