The switch is applicable to three-phase oil-immersed on-load capacity and voltage regulation distribution transformer (hereinafter referred to as capacity and voltage regulation transformer) with AC 10kV, 50Hz or 60Hz and maximum rated capacity of 160 (50) KVA to 630 (200) kVA. Under the condition that the capacity and voltage regulation transformer is on-load, the automatic capacity regulate or voltage regulation switching can be carried out respectively according to the signals sent by the switch controller (with the switch itself), SO as to adjust the capacity and output voltage of the capacity and voltage regulation transformer, to improve the power quality and reduce the loss of the capacity and voltage regulation transformer.