Based on the compressed sensing (CS) theory, an imaging process for three-dimensional (3D) objects is illustrated. In order to solve the problem that the calculation of the 3D imaging based on CS is too large, a simple method of 3D information calculation is proposed, by which only two CS processes are needed to obtain 3D information of objects located at several distances, thus reducing computation greatly. Then, the 3D imaging process is simulated to illustrate the effect of sampling rate on the precision of distance calculations. A real 3D imaging system is built, which shows that this method is workable.