The present invention relates to a photovoltaic access optimization method with the consideration of economy and security. Firstly, a distributed power maximum utilization capacity calculation model based on a tidal current constraint is established, then with the minimum sum of distributed power investment cost, new line cost, line loss cost and power cut loss cost as a target, with node voltage, line carrier, power balance, N-1 check as constraints, a power distribution network access power distribution network optimization model is established, thus the optimal access scheme of a distributed power supply is obtained, and a distributed power network expansion planning model is established. The photovoltaic access optimization method has the advantages that the power supply and a grid are effectively combined, complementary advantages and coordinated development are achieved, in the condition of a given distributed power supply planning access capacity, the specific access position of the distributed power supply is determined, grid expansion investment cost is saved, the adverse effects of the distributed power supply to the grid is minimized, and thus the effectiveness is maximized.