Unmanned aerial vehicle (UAV) is vulnerable to interference and even damage under high-power microwave (HPM) radiation, and its airborne antennas are important coupling pathways. To study the coupling response of its airborne antennas under HPM radiation, taking the datalink antenna and the navigation receiver as the research objects, their coupling models under HPM radiation are established according to the actual layout of the UAV. The accuracy of the antenna models are verified by their far-field pattern and S₁₁ parameter of the antenna. The coupling voltages induced on the ports of the datalink antenna and the navigation receiver antenna under HPM radiation with different scenarios and parameters are obtained, and typical scenario experiment is carried out to verify the simulation results. The results show that the coupling voltage induced on the port of the datalink antenna under L-band HPM radiation is higher than that under S, C and X bands HPM radiation. Compared with the horizontal polarization, HPM with the vertical polarization has better interference effect on the datalink of UAV, and the coupling voltage is linearly related to the radiated field strength and is less affected by the pulse width and the rise time of HPM. The coupling voltage induced on the port of the navigation receiver antenna under space-based HPM is higher than that under ground-based HPM. The research will provide the theoretical references in attacking UAVs with HPM weapons.