The implementation of interruptible load improves the quality of power supply and economy in power system, the optimal removal order of interruptible load should be considered from these two aspects. Based on compensation price, nodal price and line loss were divided into the economy of interruptible load for power system, and the parameters of nodal price and line loss were calculated from the Optimal Power Flow (OPF). Also, the conception of removal price was described. Then the effects of interruptible load on voltage quality and economy were respectively quantified and integrated as the optimal removal order of interruptible load. The ratio of voltage quality index to economic index was regarded as the ground of interruptible load removal order and the flowchart was proposed for power system to remove interruptible load. Finally a test of our optimal removal order of interruptible load on a simple system was carried out, and the test result proves the reasonableness and effectiveness of the proposed method.