The invention discloses an energy internet multi-energy main body energy purchase and conversion operation method, and belongs to the technical field of energy internet. The method provided by the invention comprises the following steps: establishing an energy internet multi-energy main body internal model and an energy internet multi-energy main body energy purchase and conversion operation strategy optimization model; on the premise of meeting the energy demand of scattered users, optimizing the energy purchase quantity of the multi-energy main body and the working state of the internal energy conversion device, so that the energy purchase cost of the multi-energy main body is lowest, and the economy is optimal. The method provided by the invention can provide a theoretical basis for decision making for the multi-energy main body with the energy conversion device, and help the multi-energy main body to optimize energy purchase and energy conversion operation strategies, thereby obtaining more profits in an energy internet environment.