Ta2O5 thin films are widely used in optical and microelectronic industry because of its superior optical and mechanical properties. In this paper, single-layer Ta2O5 thin films were prepared by APS plasma assisted electron beam evaporation deposition. Based on the theory of ion energy transfer, the selection criteria of APS process parameters were established. By optimizing APS source parameters, Ta2O5 thin films with different characteristics were prepared. The spectral and refractive index dispersion of Ta2O5 thin films were analyzed by Cary7000 spectrophotometer. The stress and surface roughness of Ta2O5 films were analyzed by Zygo interferometer. Experiment and analysis results showed that the characteristics of Ta2O5 thin films are closely related to APS plasma assisted processing parameters. The discharge current and bias voltage of APS source have great influence on the stress and surface roughness of Ta2O5 thin films, but have little influence on the spectral characteristics and refractive index dispersion. The influences of preparation parameters on the properties of Ta2O5 thin films were analyzed and optimization fabrication parameters were obtained. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.