Large-scale arrays are widely used due to their advantages of high gain, high resolution, and strong beam control capability. The large number of antennas leads to a sharp increase in computational complexity, and thus, it is necessary to reduce the complexity of signal processing. A signal separation method is proposed based on subarray beam synthesis. This method can improve signal reception and separation performance through zero-forcing calculation and realise system gain and phase error corrections in the front end of an antenna. Compared with back-end processing, it has the advantage of low implementation difficulty. The feasibility and performance of the method are verified by simulations.