The invention discloses a processing method of an anti-proton irradiation InP-based HEMT device based on BCB passivation. The method comprises following steps of A, preparing an InP-based InAlAs/InGaAs HEMT epitaxial wafer and carrying out cleaning and drying; B, through photoetching and corrosion, forming an active source region isolation bench face on the InP-based InAlAs/InGaAs HEMT epitaxial wafer; C, through photoetching and metal evaporation, forming a source electrode and a drain electrode on a highly-doped InGaAs cap layer and forming gate lead lines on the InAlAs buffering layer; D, through electronic beam photoetching, gate groove corrosion and metal evaporation, forming a T-type groove in the highly-doped InGaAs cap layer; E, spinning and covering the surface of the InP-based HEMT device with a BCB material, and through high temperature solidification, forming a BCB passivation layer; F, using a deep reaction ion etching device to carry out contact hole corrosion on the BCB passivation layer; and G, through photoetching and metal evaporation, forming a test electrode on the BCB passivation layer on the upper part of a contact hole. According to the invention, the anti-photon irradiation capability of the InP-based HEMT device is effectively improved; a planarization wiring environment is created; and a firm base is laid for development of anti-irradiation integrated circuits.