The invention is applicable to the field of radio frequency communication, and provides a harmonic power amplifying circuit with high efficiency and a wide bandwidth and a radio frequency power amplifier. The circuit comprises an input matching network, a transistor and an output matching network; a grid electrode of the transistor is connected with an output end of the input matching network, a drain electrode of the transistor is connected with an input end of the output matching network, and a source electrode of the transistor is grounded; the output matching network causes a lower sideband of the harmonic power amplifying circuit to work in a continuous inverse F amplification mode and causes an upper sideband of the harmonic power amplifying circuit to work in a continuous F amplification mode; and the output matching network and a parasitic network of the transistor form a low pass filter. According to the harmonic power amplifying circuit provided by the invention, due to the transition from the continuous inverse F power amplifier working mode to the continuous F power amplifier working mode, the efficiency of a continuous harmonic control power amplifier is effectively improved to be higher than 60%, a relative bandwidth is improved to be higher than 80%, and the harmonic impedance is simple to match and easy to realize.