An optical multi-beam synthetic system based on differential true time delay network which is with micro-optical array is proposed, and the relationships among the structural parameters and the beam-forming performance of the proposed system are studied. The initial phase and the consistence of amplitude and phase are optimized when we optimize the parameters of differential true time delay network based on micro-optical array. The directional diagrams of antenna elements are optimized when we optimize the structural parameters of antenna elements, and the problems of existing grating lobe and wide beam in beamforming are solved. At last, the grating lobe is suppressed, the extinction ratio of sidelobe is larger than 10 dB, the 3 dB bandwidths are 35° at 3.8 GHz and 29° at 4.9 GHz, the steering error is less than 1.5°, and the frequency covering band is 2-6 GHz. The proposed system has wide application prospects in optically controlled phased array radar.