The invention discloses an electric-heat comprehensive energy system optimization dispatching method considering heat accumulation characteristic of a heat supply network. By virtue of synergy of source, network and load, the consumption level of the renewable energy sources is improved; on the source side, electric heating equipment decoupling is performed for ordering power by heat; on the loadside, the demand side response capability is reinforced flexibly by a thermal load; on the network side, the power network has the characteristics of easy transmission and difficult storage, and the heat supply network has the characteristics of easy storage and difficult transmission; due to time delay from the heat source to user heat supplying, the heat supply network obtains the natural heat storage characteristic; a refined heat supply network model, considering the thermal dynamic characteristics of heat supply time delay, heat supply loss and the like, is established according to the physical structure of a thermodynamic system; by virtue of the complementary characteristic of an electric power system and the thermodynamic system, the consumption level of the renewable energy sources can be improved, and adjustment flexibility of the system can be enhanced; and by virtue of the method disclosed in the invention, the problem in new energy consumption caused by large-scale centralized grid connection can be solved effectively.