Abstract: With the development of vacuum electronics technology, electron multipliers with high gain, fast response and long service life are required by a variety of instruments and devices to improve their overall performance. To meet the demand for high-performance electron multipliers in the field of vacuum electronics, this paper investigates a Zr-doped MgO-Au thin film. First-principles calculations for Zr-doped MgO were performed using the CASTEP module embedded in Materials Studio. Analysis of the electronic structures of geometrically optimized supercells reveals that Zr doping reduces the band gap of MgO crystals and lowers the work function of specific crystal facets. This provides theoretical guidance for subsequent experimental investigations. The films were prepared by magnetron sputtering, and their secondary electron emission performances were measured and compared with those of the MgO-Au thin film. Through various characterization techniques, in-depth analyses of film performance were carried out. The results show that, compared with MgO-Au thin films, Zr doping concentrations in the range of 0.06 % to 0.18 % can effectively improve the secondary electron emission performance of the film. Gradually increasing Zr doping concentrations causes such performance improvement to first increase and then decrease, with the optimal effect achieved at a Zr doping concentration of 0.12 %. This provides an important process window reference for the engineering application of this film.