The utility model discloses a cascaded damping sheet device of marine LNG tank, the device include and a plurality ofly swing hindering that board, pivot and torsion spring constitute and swing the unit by hindering, are cascaded transversely the installation in C type LNG tank. Hindering and swinging the board and install in the pivot, both sides are equipped with torsion spring, and the three organically forms one and takes damped hindering and swing the unit, the utility model discloses the simple novelty of structural style can reduce the interior liquid of LNG tank effectively and rock. Fully consider the liquid degree of rocking of the different positions of tank in addition, hinder and swing the unit and be the step distribution, low in the middle of the tank, two is high, further improve to hinder swings efficiency. The device designs dexterously, simple and practical, and engineering application nature is strong, hinders that to swing the effect obvious, is one kind and gathers around tank with broad prospects for development and hinder and swing the device.