A constant current power supply with a plurality of current outputs for LED lamps includes a DC/DC control module, an overvoltage detection circuit, a current sampling resistor, at least one output current conversion circuit and at least one overvoltage protection resistor. The output current conversion circuit includes a switch, a MOS transistor with a grid electrode electrically connected to the switch, and a current conversion sampling resistor. The overvoltage protection resistor is connected in series between the two voltage sampling resistors and the grid electrode of the MOS transistor. The constant current power supply of the present invention can output various current values through the output current conversion circuit so as to be able to adapt to different LED loads. One power supply can be applied in a variety of applications.