A Doherty power amplification device, comprising: a first amplification branch, a second amplification branch, a harmonic injection unit, and a first output matching unit, wherein the first amplification branch comprises a first amplifier, wherein the first amplifier receives a signal having a first frequency; the second amplification branch comprises a second amplifier, wherein the second amplifier receives a signal having the first frequency and a second frequency, the second amplifier is turned off for an input signal of the first frequency that has a power value lower than an enabling threshold, the second frequency is N times the first frequency, and N is an integer greater than 1; and the harmonic injection unit comprises a first input terminal, a second input terminal, a first output terminal, and a second output terminal, and the first output matching unit comprises a third input terminal and a fourth input terminal, wherein an output terminal of the first amplification branch is connected to the first input terminal of the harmonic injection unit, an output terminal of the second amplification branch is connected to the second input terminal of the harmonic injection unit, the first output terminal of the harmonic injection unit is connected to the third input terminal of the first output matching unit, and the second output terminal of the harmonic injection unit is connected to the fourth input terminal of the first output matching unit; the harmonic injection unit is configured to inject an input signal of the second frequency that is input from the second input terminal to an input signal of the first frequency that is input from the first input terminal, to obtain an input signal of the first frequency that has undergone harmonic injection and to output the first input signal having undergone harmonic injection from the first output terminal; wherein the first output terminal is configured to be turned on for the signal of the first frequency that is input from the first input terminal, the second output terminal is configured to be turned on for a signal of the first frequency that is input from the second input terminal, and the first output terminal and the second output terminal are configured to be open for the signal of the second frequency; and the first output matching unit is configured to: combine signals that are input from the third input terminal and the fourth input terminal, and output a combined signal; wherein the harmonic injection unit comprises: a harmonic injection subunit, a first matching subunit, and a second matching subunit, wherein a first terminal of the harmonic injection subunit is separately connected to the first input terminal and one terminal of the first matching subunit, and a second terminal of the harmonic injection subunit is separately connected to the second input terminal and one terminal of the second matching subunit, wherein the harmonic injection subunit is open for the signal of the first frequency, and is turned on for the input signal of the second frequency that is input from the second input terminal; the other terminal of the first matching subunit is connected to the first output terminal, wherein the first matching subunit is configured to be turned on for the input signal of the first frequency, and is configured to be open for the input signal of the second frequency; and the other terminal of the second matching subunit is connected to the second output terminal, wherein the second matching subunit is configured to be turned on for the signal of the first frequency that is input from the second input terminal, and is configured to be open for the signal of the second frequency that is input from the second input terminal.