Abstract: Urban power grids undertake the dual tasks of electricity transmission and distribution, and their safe and economic operation directly affects urban stability and development. However, the traditional dispatching mode that separates transmission and distribution networks is difficult to achieve globally optimal operation of the urban power grid. To address this issue, this paper proposes a cooperative dispatching method for urban transmission-distribution networks incorporating UPFC (unified power flow controllers) based on a master-slave game. In this method, the transmission network dispatcher acts as the leader, employing linear programming to optimize its operational strategy and publishing boundary bus voltage information to the distribution network dispatchers. Each distribution network dispatcher, as a follower, optimizes its local dispatching scheme accordingly and feeds back boundary power information to the leader. This iterative optimization process continues until the deviations of boundary voltages and powers between two consecutive iterations fall below specified thresholds. To validate the effectiveness of the proposed method, a single-snapshot case study is first conducted using the 39-bus system from Matpower as the transmission network, with 15-bus and 10-bus systems connected to buses 12 and 26, respectively, serving as distribution networks. Subsequently, a multi-period case study is carried out based on actual operational data from a typical day in the eastern district of the Zhuhai power grid. The results demonstrate that, compared with the traditional decoupled dispatching mode, the proposed cooperative dispatching method exhibits significant advantages in reducing network losses and dispatching costs, thereby verifying its engineering practical value.