The invention relates to a device and a method for modifying resonance drift of a switch converter, in particular to a device and a method for modifying resonance drift of a serial connection resonance switch converter by using a table checking method. The invention solves the problem that the non-zero cutoff of the converter switch can be caused by the resonance frequency drift in a capacitor charging power supply designed on the basis of a serial connection resonance switch converter technology in the prior art. In the device and the method for modifying the resonance drift of the serial connection resonance switch converter by using the table checking method, when the resonance frequency drifts, the conduction time of the converter switch is changed, and the relationship of the resonance frequency and the converter switch time is maintained unchanged, so the converter is always in the zero current switch state. The device is characterized by comprising a converter, a resonance circuit, a transformer, a rectification circuit, an energy storage capacitor, a driving circuit, a digital controller and a table checking module, wherein the digital controller is electrically connected with the table checking module. The invention is mainly applied to occasions with the zero current state of the serial connection resonance switch converter type capacitor charging power supply.