The invention discloses a multi-mode power amplifier. The multi-mode power amplifier is of three power mode, namely, a low power mode, an intermediate power mode and a high power mode, and comprises a regulation control circuit, an AMP (Amplifier) 1, a shunt device, an AMP 2, and a low power output matching circuit, an intermediate power output matching circuit and a high power output matching circuit. Under the low power mode, the regulation control circuit controls the AMP 1 to work in the first power mode, and controls the shunt device to connect the output end the AMP 1 to the low power output matching circuit; under the intermediate power mode, the regulation control circuit controls the AMP 1 to work in the second power mode, and controls the shunt device to connect the output end of the AMP 1 to the intermediate power output matching circuit; under the high power mode, the regulation control circuit controls the AMP 1 to work in the second power mode, and controls the shunt device to connect the output end of the AMP 1 to the AMP 2; the output end of the AMP 2 is connected with the input end of the high power output matching circuit. In this way, the two amplifying units can be only used to realize low, intermediate and high power modes. Therefore, the occupied chip area is small, and the manufacturing cost is relatively low.