A calculation parameter and a constitutive model for greenhouse film were obtained by a uniaxial tensile test. And a calculation model of the load effect for the greenhouse film was developed by the nonlinear finite element method and the method with artificial stiffness was applied. According to the relative criterion, the safety coefficient of bearing capacity for the greenhouse film was discussed. Based on the models and methods mentioned above, the example for the bearing capacity of the film was calculated on the working conditions of snow and wind load, and the first principal stress and deformation of the film were obtained. In addition, the influence of different pre-tensions on the bearing capacity of the film, and the concrete distribution of first principal stress were discussed. This paper presented the calculation model and theoretical method for the proper application of the film in the greenhouse design.