Abstract: In order to theoretically analyze and calculate the optical film-thickness distribution deposited on the surface of large curvature spherical accessory, we firstly determined the processing configuration, then determined the calculation function formula through mathematic model, finally carried out the calculation through numerical integration when the evaporation source was point evaporator (n=0) and plane evaporator (n=1, 2) respectively. Results of the calculation were compared with the experiment results. It is revealed that the calculation results when n=2 accord with the experiment results well under the processing conditions determined in this paper. It is also proved that the film-thickness deposited on the surface of large curvature spherical accessory can be calculated by numerical calculation adopting the designed modeling method and appropriate beam characteristics of evaporation source.