A radio frequency interference suppression circuit that includes a reference ground end, a main power circuit, a driving circuit and an impedance unit is provided. The main power circuit includes a first switch that includes a control end, a first and a second end. A minimal impedance is presented between the second end and the reference ground end. The driving circuit is coupled to the control end and the second end. The first impedance unit is formed between the second end and the reference ground end in a high frequency differential mode loop to reduce a high frequency voltage drop therein. The first switch receives a driving signal from the driving circuit to be turned on or turned off between the first and the second ends accordingly to make the main power circuit converts a first power signal to a second power signal.