Greenhouse membrane exposed to the atmosphere, by the sun, temperature, humidity and other factors, the function of the film to form damage, greatly reducing the use of agricultural film life. In the use of plastic greenhouses, we experience that the use of Long-life agricultural film on energy conservation, saving human resources, reduce environmental pollution is very advantageous. In foreign countries, the agricultural film is almost 100% of long life, and the application of weather-resistant membrane has been developed rapidly in recent years. The cracking elongation of the film is the main target of evaluating the service life, usually, we use the time limit of the cracking elongation of the agricultural canopy film to the initial value of 50%. Natural atmospheric exposing experiment is the most effective method to evaluate the weathering resistance of greenhouse membrane, which can provide accurate guidance for the application of agricultural greenhouses.