Abstract: Abstract: The existing standards are difficult to characterize the characteristics of silage PE film under actual working conditions. In the article, uniaxial tensile tests at different tensile rates (strain range controlled within 200%) and stress relaxation tests at different initial elongation rates were conducted on PE film specimens in MD and TD directions. The results from the tensile tests highlight a pronounced dependency on both stretching speed and direction in the stress-strain (σ-ε) profiles, with the films exhibiting secondary yielding phenomena in both MD and TD orientations. As the rate of stretch increased, a decrease in the elongation at second yield was observed. The first and second yield strengths in the MD direction show a good linear mapping relationship with the (logv). The increase of tensile rate can improve the yield strength of PE film, but after reaching a certain rate, the yield strength will reduce the toughness of PE film. Stress relaxation tests revealed that, across a spectrum of initial stretch levels from low (10%) to high (70%), both MD and TD oriented films demonstrated a rapid decrease followed by a gradual reduction in stress. The generalized seven-element Maxwell model accurately described the PE film's stress relaxation behavior, offering insights into its long-term stress relaxation characteristics. With increasing stretch levels, the quantity of stress relaxation and the rate of stress decay decreased, indicating a reduction in the relaxation modulus and a more stable modulus during the slow stress decline phase. These findings suggest that for optimal silage sealing, PE films should balance stiffness with resilience to relaxation, with an ideal stretch range of 50 ~ 70% during wrapping.