The invention discloses a determining method of photovoltaic transmission power limit considering variable correlation. According to the method, a random planning problem is built, the photovoltaic transmission power limit maximization is set as a target function, the correlation inside a photovoltaic power station, the correlation between region loads and the correlation of the photovoltaic power generation and the node load change are considered, the constraint conditions are inspected through the sampling on the photovoltaic power output, the traditional machine unit power output and the load level on the basis of a Latin hypercube sampling method, finally, an improved bacterial foraging algorithm is used for solving a planning problem, and the photovoltaic transmission power limit conforming to the conditions is calculated. The method provided by the method has the advantages that the problem of potential safety hazard after the photovoltaic network accessing since the photovoltaic transmission power limit does not conform to the actual production practice is solved, the planning work of the photovoltaic power station can be better guided, the sampling coverage rate is increased, the calculation quantity is reduced under the condition of not influencing the precision, the early stage optimization speed is accelerated, and meanwhile, the later stage optimization precision is also ensured.