Abstract: To describe the affections of power system operational parameters such as the uncertainty of wind power fluctuation etc. on power grid and to master the interval power flow distribution in the grid, based on interval arithmetic and affine arithmetic, an optimal interval power flow calculation method for AC/DC hybrid power system containing DC power flow controller (DCPFC) was proposed. Firstly, an interval power flow model was established by rationally utilizing interval arithmetic and affine arithmetic, and the static security performance index (SSPI) sensitivity computing method was used to determine the optimum location in DC grid to configure the DCPFC. Secondly, an interval power flow optimization model containing DCPFC was established, by which such uncertainties as the power output generated by new energy and so on were expressed as interval variables. And then giving consideration to both network loss and static security of power grid the established mathematical model was solved by elitist strategy based Fast Non-Dominated Sorting Genetic Algorithm II (NSGA II) to obtain the Pareto optimal solution uniformly distributed in space. Finally, the proposed method was verified by MATLAB simulation example. Simulation results show that the proposed method can make both network loss and static security indices of power grid tending to optimum under the wind power fluctuation.