Abstract: As a new type of demand-side adjusting device, the electric spring (ES) forms a smart load in series with non-critical loads with a wide voltage range to automatically adjust the power consumption to match the power generation so as to optimize the operation of ADN. In this paper, the optimal power flow (OPF) model of ADN with ES is researched, and a smart load optimization method based on fruit fly optimization algorithm is proposed, and approximation technique is used to derive the second-order cone programming formula of OPF. The active adjustment of the smart load can reduce the voltage deviation, the transmission loss, and the operational cost of ADN. The proposed multi-objective optimization model is used in a modified IEEE 33-bus distribution system. Simulation results validate the proposed optimization model and algorithm.