With the developments of deep sea and marginal oil fields, FPSO has been widely used in offshore oil and gas field development.FPSO, as an oil and gas production device with both energy production and consumption, takes an economic energy distribution scheme on the premise of meeting its energy demand, which not only helps to reduce construction costs, but also helps to improve the energy efficiency of the entire system and promote energy conservation. Taking the annual total cost of energy system as the objective function, the MILP model of FPSO distributed energy system is established and solved under the conditions of energy balance and technical constraints to determine the equipment selection and capacity, and the corresponding operation plan to achieve the purpose of energy conservation and consumption reduction. The model is validated by an example of FPSO in the Bohai sea. The results show that the cost of distributed energy system can be reduced by 14.6% compared to traditional operating schemes. In addition, considering the impact of different energy prices on the economy of the system, it is found that the increase in natural gas prices has a great impact on the design and operation of DES.