A new interface power control method based on DC power flow and sensitivity analysis is presented. In the proposed algorithm， firstly， DC power flow is used to calculate the matrix of generation shift distribution factor（GSDF）. Further， according to the needs of power control， using the information of GSDF matrix， the control scheme can be obtained through nonlinear optimization. By this algorithm， the total power flow of the interface can be controlled exactly and， furthermore the constraints of power exchange between different islands can be satisfied. The proposed algorithm is validated by some systems， such as New England 39-bus system， IEEE 118-bus system， et al. It is revealed that the method can exactly control the interface power in large-scale systems and has a good application prospect.