An on-load voltage regulation tapping switch of a transformer is composed of a tapping switch unit and a switch control circuit. The tapping switch unit is composed of two relay switch contacts (K1, K2) and corresponding contact protection circuits. One end of each of the two switch contacts (K1, K2) is connected to corresponding transformer winding taps (1, 2), and the other end is connected to a power supply after being connected in parallel. Two switch contact protection branch circuits are a series circuit of an MOS transistor (T1) and an auxiliary relay contact (K11) and a series circuit of a diode (D11) and the auxiliary relay contact (K11) respectively. The two series circuits are connected to two ends of the corresponding switch contact (K1) in parallel respectively. Multiple such tapping switch units are connected to one another in parallel to form a multi-winding branch tapping switch. The switch control circuit controls all main switches, auxiliary switches and MOS transistors (T1) to act according
