Abstract: To prevent frost heaving damage, double plastic films can be laid under lining plate which can unbind adfreezing constraint between lining and frozen soil. This kind of canal is just called lining canal with double films. In order to explore its effect and mechanism, finite element software ADINA was applied to simulate canal heaving process and the rules of stresses and deformations of lining plate were also analyzed. Compared with the normal lining canal, lining canal with double films can get an obvious effect of anti-frost heave, because it can make frost heaving distribution and force more uniform to reform stress states remarkably. For mean square deviation and extremum of tangential adfreezing force on shady slope, bottom and sunny slope, the decreasing amplitude is greater than that of normal frost-heave force. And this fact demonstrates that lining canal with double films can weaken the constraint to make frost heaving distribution uniform and reform stress states, which is the mechanism of anti-frost heave. Compared with trapezoidal section, the trapezoidal with arc-bottom is suitable section for lining canal with double films. And its elastic joints between arc-bottom plate and that on slope should be managed elaborately, or integral structure should be applied to avoid sliding instability of plates on slope. The results can provide scientific references for further research and extended application of lining canal with double films.