A switching regulator having an energy saving circuit and an energy saving method is provided to improve the system efficiency under light load conditions. A first control unit outputs an oscillation signal and an energy saving signal in response to the variation of a feedback signal. A second control unit receives the feedback signal and the oscillation signal to output a switching signal to control a switch. An off-time of the switching signal is increased in response to a decrement of the load. The energy saving signal is applied to turn off the switch and the circuits of the switching regulator needn't to work during the off-time of the switching signal for saving energy under light load conditions.