The invention provides a temperature adjustment method for an inner-outer-wall-structured heat preservation device and the heat preservation device implementing the temperature adjustment method, relating to a method for transferring heat between inner and outer walls in a sealing cavity of the heat preservation device and further relating to a multifunctional heat preservation device with heating and cooling functions. The heat preservation device comprises an outer wall (1), an inner wall (2), a controllable heat transfer medium (3), a heat transfer boss (4) and a limiting structure (7). Under a heat preservation state, the heat transfer medium (3) is only in contact with the outer wall (1) or the inner wall (2), and a thermal insulation state is formed between the inner and outer walls in the heat preservation device. Under a heat dissipation state, the heat transfer medium (3) is fit with the heat transfer boss (4) between the inner and outer walls of the heat preservation device, and heat is transferred through the inner wall (2), the heat transfer boss (4), the heat transfer medium (3) and the outer wall (1). Under the action of the limiting structure, the heat preservation device can be in a reliable heat preservation or heat dissipation state no matter when the heat preservation device is placed upwards, downwards, obliquely and transversely or when the people move. The heat preservation device provided by the invention has a reliable heat preservation function and is capable of heating and cooling under a sealing state, so that the pollution of liquid to air is avoided, and meanwhile, sprinkling and scalding are prevented; and the heat preservation device can be used as a warming device in cold winter.