The invention discloses a high-frequency filter, which comprises a triangular wave generating circuit, a first MOS transistor, a second MOS transistor, a third MOS transistor and a fourth MOS transistor, wherein gates of the first MOS transistor, the second MOS transistor, the third MOS transistor and the fourth MOS transistor are all coupled with the triangular wave generating circuit; and the triangular wave generating circuit comprises a high-frequency buffering circuit, a waveform generating circuit and an amplification circuit. According to the high-frequency filter, a corresponding power supply can be inverted effectively according to power of an external power supply through the triangular wave generating circuit, the first MOS transistor, the second MOS transistor, the third MOS transistor and the fourth MOS transistor; through setting of the high-frequency buffering circuit, the waveform generating circuit and the amplification circuit, when a high-frequency component in the external power supply enters the filter, the high-frequency component can be effectively converted into a low-frequency component, a corresponding power supply in the case of low frequency can be inverted, the filter cost is reduced, and the high-frequency filter effects of the filter are enhanced.