The invention discloses an input voltage mode identification method. The method comprises the steps: receiving three-phase input voltage, performing sampling processing on each input voltage to obtain a variable value of the three-phase input voltage counter, wherein the three-phase input voltage comprises an a-phase input voltage Va, a b-phase input voltage Vb and a c-phase input voltage Vc, and the values of the variables of the three-phase input voltage counter comprise the value of the variable of the a-phase input voltage counter, the value of the variable of the b-phase input voltage counter and the value of the variable of the c-phase input voltage counter; and judging the type of the input voltage according to the variable value of the three-phase input voltage counter and the three-phase input voltage. The input voltage mode identification method provided by the invention can be compatible with multiple input modes, does not need to be redesigned for different input voltage types, is high in universality and short in development period, saves the cost, and is convenient for a user to use.