Abstract: To address the limitations of emission aperture size and output power in on-chip optical phased arrays, this study focuses on laser coherent combining technology based on a multi-aperture one-dimensional array grating antenna with chip-integrated multi-fiber parallel access, conducting a comprehensive theoretical analysis and experimental validation. A simulation model was established based on the output optical field characteristics of the photonic chip to analyze the impact of piston phase errors on beam combining performance. An experimental demonstration of chip-based 4-aperture laser coherent combining was implemented using the SPGD algorithm. Each aperture, comprising 1024 silicon optical waveguides, achieved a physical dimension of 1.8 mm×4.3 mm. The system demonstrated remarkable phase control accuracy of λ/66.16 ("λ" represents the wavelength), with the PIB metric showing an 8.81-fold enhancement after coherent combining and a sidelobe suppression ratio of 10.89 dB. These results effectively validate the feasibility and effectiveness of the proposed chip-based multi-aperture one-dimensional array grating antenna coherent combining technology.