This invention relates to a method of speed control selection for an electronically commutated motor comprising the following steps: (a) a motor controller receives an input signal T from a speed control selection circuit; (b) the motor controller retrieves a corresponding value for a motor running speed S from a comparison list correlating the input signal with the motor running speed, which list has been stored in the motor controller in advance, by searching the comparison list for the input signal T; and (c) the motor controller controlling a motor M to run at the motor running speed S, achieving the purpose of the speed selection. This method allows for from 2 to 256 speed choices with a single signal wire only. Such a circuit structure has the advantages of high integration, simple wiring, low cost, good performances, low failure rate, higher number of optional speeds, and simpler and more practical control.