Existing power system planning does not consider short-term security constraints, and does not reserve sufficient active power for short-term control after a fault, especially in the case of a DC blocking fault in the power system with UHVDC connection. In this case there will be a large amount of active power deficiency, resulting in a large area of load shedding after the fault. This brings serious economic losses to the power system. Therefore, this paper proposes an OPF model of the receiving side of the power system considering short-term operation security constraints. First, several N-1 faults including DC blocking are set in the system. Secondly, short-term security constraints are added to the optimal power flow planning model under the traditional N-1 security constraints. Finally, taking the minimum generation and transmission cost and the minimum load shedding cost as the objective function, an OPF model for the receiving side of the power system with UHVDC connection is proposed. The model is verified in the modified IEEE39 node system. This work is supported by the National Natural Science Foundation of China (No. 52007057), the Innovative Construction Program of Hunan Province of China (No. 2019RS1016), and the Excellent Innovation Youth Program of Changsha of China (No. KQ2009037).