The present invention discloses a switching regulator compatible with an electronic transformer and a control method thereof. The switching regulator includes: a power stage circuit, a control circuit, and an input current peak & valley setting circuit. The control circuit is coupled to the power stage circuit, for generating an operation signal according to a feedback signal and a peak & valley setting signal, to operate at least one power switch in the power stage circuit, so as to convert a rectified input voltage to an output voltage. The input current peak & valley setting circuit is coupled to the control circuit, for generating the peak & valley setting signal such that in one cycle period, the input current has multiple valleys forming a semi-sinusoidal contour.