Abstract: For the purpose of reducing the data transmission load of formationflying small satellites and speeding up the imaging rate for formation-flying small satellites Synthetic aperture radar(SAR),a technical approach based on the theory of space-time compressive sensing is proposed.Firstly,on the basis of researching and analyzing the sparse characteristic of formation-flying small satellites SAR echoes, the space-time compressive sensing(CS)algorithm is presented.Then,the echo sparse model and the target restore matrix are established.Finally,the minimum l₁ norm algorithm used for time dimension and space dimension recover reconstruction is studied,and fast,low-load imaging is implemented.The effectiveness of the scheme is tested through processing simulated data.