The present disclosure provides a single carrier based multilevel modulation method, a single carrier based multilevel modulation device, and a storage medium. In each control period, a modulated wave value corresponding to each of n switch pairs is obtained according to a reference voltage to obtain n modulated wave values, a triangular carrier having an amplitude of n is generated and compared with each of the n modulated wave values to obtain control signals for each of the n switch pairs, and for each phase, the control signals are input to the corresponding switch pairs of the phase bridge.