The treatment and settlement mechanism of deviation power is on important standard to judge whether the transaction mechanism is fair and reasonable. Whether the treatment and settlement mechanism is appropriate will directly affect the economic interests between market subjects and the promotion degree of market reform. Based on the summary of the current treatment and settlement mechanism of deviation power in the domestic power market, taking Guangxi as an example, the current deviation treatment, settlement mechanism and existing problems in the power market are dnalyzed, two deviation treatment and settlement mechanisms based on the idea of uncoupling plan and market and monthly pre-listing are designed, and the safety of the implementation of the monthly pre-listing mechanism constrained unit commitment and safety constrained economic scheduling model are corstructed.Finally, through the comparative analysis of the two deviation han-dling mechanisms, the phased implementation suggestions are putforward from the idea of no decoupling between plan and market to the idea of monthly pre-listing, and to the market transaction deviation handling and settlement mechanism under the spot market mechanism.