Abstract: The gradual implementation of the “dual carbon” goals has led to the continuous expansion of the grid-connected scale of distributed photovoltaic. Due to the uncertainty of output and the harmonic interference caused by the nonlinearity of power electronic devices, the problem has become increasingly severe. This paper combines the requirements of harmonic suppression and multi-source coordination control for distributed photovoltaic grid-connected systems. On the one hand, it studies the causes of harmonics generated by photovoltaic inverters and their impact on grid impedance. On the other hand, it summarizes several commonly used harmonic suppression techniques and proposes an improved repetitive control- based harmonic current suppression scheme. Then, a multi-inverter coordination control structure diagram considering the randomness of photovoltaic power generation output is established, achieving the goal of reasonable active power sharing and joint elimination of harmonic currents. Finally, simulation experiments are conducted using MATLAB/Simulink, and the results show that the proposed system can effectively coordinate control among multiple inverters. The research indicates that this scheme can reduce the total harmonic distortion of grid-connected current to below 2.5% while enhancing the system’s adaptability to weak grids.