The invention discloses a main transformer medium-low voltage side bus voltage overrun processing method based on voltage regulation function. The invention defines the voltage regulation function ofvoltage regulation equipment to the overrun node voltage to regulate moment. Similar to the torque action in the mechanical field, the regulating torque is defined as the product of the regulating force and the regulating distance. The adjustment torque, adjustment time and adjustment cost are weighted and summed to form the adjustment function of the adjustment point to the node exceeding the limit. The size of the adjustment function is sorted by two-way bubble sorting method, and the adjustment strategy candidate set is selected according to the sorting results. The invention reduces the range of the adjustment variable selection and simplifies the adjustment procedure through the utilization of the candidate strategy set. The method of the invention has the advantages of fast executionspeed and saving computational memory.