More and more renewable energy is connected to the distribution network (DN), and some DNs in suburban or rural areas connect multiple electrothermal loads to balance renewable energy power. The electrothermal load includes heat storage, heat exchanger, and heating network. In this paper, the power flow method is used to analyze the heat transfer process of electrothermal load. Considering the minimum voltage deviation, the minimum active power loss of DN, and the minimum carbon emission cost, the overall electrothermal hybrid optimal power flow analysis is carried out to achieve multi-objective optimization. In this paper, the power flow method and carbon emission cost method are applied to the optimal power flow analysis of the electrothermal hybrid network. The effectiveness and correctness of the model are verified by an improved IEEE 33 buses case.