The formulation of the tie line schedule in Central China power grid is a heavy workload and complex process， while the existing artificial establishment mode for large power system will not be able to accommodate the subsequent grid-provincial coordination plan. For this reason， a linked list model of electricity trade and tie line schedule and a tree cluster model of large trans-regional power source and tie line are proposed according to the actual situation of the Central China power grid. Based on the former model， a plan making optimization model is proposed with minimum adjustment as the optimization objective and the contract power quantity， power output and transmission power of tie line as constraints. The optimization model is solved with ergodic technique based breadth-first search and cyclic iteration. The model contains a complete description of various problems of the tie line schedule in the Central China power grid， realizing automatic formulation and flexible adjustment of the schedule. Actual operation results show that the proposed model is valid and effective， while simulation results exhibit the unique technical advantage of the model for tie line schedule adjustment.