Abstract: The target, as the core component of a compact deuterium-deuterium neutron generator, has a decisive impact on the neutron yield and steady-state operation of the device due to its deuterium storage performance. To inhibit the decrease in deuterium enrichment in the target coating caused by the diffusion of deuterium particles to the target substrate, the introduction of a deuterium-resistant coating is considered as an effective technical approach. This paper systematically studies the application of alumina deuterium-resistant thin coatings in neutron generator targets, focusing on four aspects: coating preparation process, surface morphology characterization, deuterium-resistant performance testing, and neutron yield evaluation. In terms of coating preparation, to ensure the structural compactness of the coating, magnetron sputtering technology is adopted to deposit a 1 μm-thick pure aluminum layer on the surface of an oxygen-free copper target substrate, and then is converted into an alumina thin coating through natural oxidation in ambient air. Scanning electron microscopy is used to analyze the surface and cross-sectional morphologies of the coating. The results show that despite the presence of micron-scale gaps on the surface, the cross-section of the coating exhibits a uniform and dense microstructure. Furthermore, deuterium permeation behavior at different temperatures is studied on a gas-driven permeation experimental platform. The results show that the deuterium permeation resistance factor （PRF） of the alumina coating reaches 145, 153, and 138 at temperatures of 750 K, 850 K, and 950 K, respectively, demonstrating good deuterium-resistant stability at high temperatures. Finally, practical application tests in neutron generator targets show that under irradiation conditions with a deuterium ion beam energy of 60 kV and a beam intensity of 4.82 mA, the total neutron count of the target without a deuterium-resistant layer is 24255, while that with the coating increases to 28335, with a neutron count increase of approximately 17%, verifying the effectiveness and engineering application potential of the alumina deuterium-resistant layer in improving the performance of neutron generators.