The present invention discloses a switching power converter with low common mode noise. The switching power converter comprises at least a switch with at least a terminal wherein said switch turning on and off alternatively which generates a plurality of noise voltages, and the noise voltage having a jump point and a static point wherein the jump point is one of said inductive component terminals, the capacitive component terminals and the second and third terminal of the switch; and an additional impedance connected between the static point and the jump point of different noise voltage to neutralize common noise current. In addition, another switching power converter having primary side and secondary side can be used to reduce the common mode noise by adding some additional impedance between the static points and jump points of the primary side and secondary side.