The energy method was used to analysis the flexural property of acrylate waterproof membrane in local loads during the period of construction and service. The membrane was formed by spraying-membrane waterproof technique for tunnel engineering. The maximum central deflection of the clamped circular plate was calculated in the uniformly distributed and concentrated loads. The minimum safety thickness was calculated in theory during the course of using. It was expected to provide theoretical reference for the further improving of spraying-membrane waterproof technique.