The invention relates to a method for maximizing transmission capacity of a multi-source transmission channel of VSC-HVDC, and the method includes the steps of establishing a grid simulation calculation model containing VSC-HVDC; studying the influence of a VSC-HVDC control mode and parameters on AC system stability; determining a VSC-HVDC control mode and parameters; calculating the sensitivity of the influence of the output of each power source on the transmission capacity of the transmission channel when N-1 checking is satisfied, and determining the priority of the output of the power source in the normal mode; calculating the measure amount of the power reduction of each power source after the N-2 fault, and determining safety control measures after the N-2 fault. The present invention guarantees maximum utilization of the transmission capacity of the transmission channel in three aspects of VSC-HVDC control mode and parameter selection, power source output arrangement under normal mode and determination of safety control measures after fault, the method is simple in calculation, clear in flow chart and convenient for engineering application.