A method for sealing a liquid composite spring, comprising: step 1, placing a sleeve-shaped outer wall (1) around an upper portion of a core shaft (3), and forming an upper liquid chamber (11) and a lower liquid chamber (12) inside the outer wall (1); and step 2, arranging a sealing member (2) at a bottom of the outer wall (1) to seal the lower liquid chamber (12), wherein the sealing member (2) is made of flexible material. The liquid composite spring is provided with the rigid outer wall and the flexible sealing member. The volume and shape of the lower liquid chamber can be changed through the flexible sealing member, so that the chamber is formed as a flexible chamber.