The invention discloses a method for determining the maximum deflection of a circular film with maximum deflection under elastic limitation. The method comprises the following steps: a uniform load qis applied to the circular film which is initially flat and fixedly clamped at the periphery in the transverse direction, wherein the Young's modulus of elasticity of the circular film is E, the Poisson's ratio is v, the thickness is h, the radius is a, and the self-weight per unit area is q0, the circular film is enabled to generate an axisymmetric deformation so as to push a rigid circular platewith a smooth surface to parallelly move by a distance of wm, wherein the radius of the rigid circular plate is a, the center of the rigid circular plate is on the same axis with the center of the circular film, the rigid circular plate is always parallel to the initially flat circular film, the axially symmetrically deformed circular film forms an interacting contact area with the radius of b with the rigid circular plate, the rigid circular plate moving in parallel compresses a spring with a stiffness coefficient of k by wm from the original length L, and then, after ignoring the self-weight of the rigid circular plate, the maximum deflection wm of the circular film after axially symmetric deformation is determined based on the static balance analysis of the axisymmetric deformation ofthe circular film by utilizing a measured value of the load q.