With the gradual opening up of the power market, the injection of outside lowprice electricity brings great challenges to the power purchase decision of receiving object. On the background, this paper classifies and sorts out the purchasing cost of different purchasing channels in the electricity plan and market, and then analyzes a series of constraints which needs to be considered in the acrossprovinces /and acrossregions power purchasing. Thus, a monthly trading decisionmaking framework is put forward for the electricity plan and market coordination with the acrossprovinces /and acrossregions trading. In addition, for the purpose of minimizing the total power purchase cost, the power flow safety constraints, on the ultra high voltage direct current (UHVDC) tie line and interprovincial transmission channel constraint are considered. Finally, the Hunan power grid is taken as an example. The influence of crossprovince and crossregion power purchase constraints on the power purchase results is discussed to verify the effectiveness of the proposed model.