Abstract: Disclosed is a method for calculating a transient overvoltage at a direct current (DC) sending end by taking into account a dynamic process of a control system. First, a first reactive power consumed by a converter station is calculated based on system operation parameters and a DC closed-loop transfer function. Then, a transient voltage change rate is calculated based on the first reactive power and a second reactive power on an alternating current (AC) side. Finally, the transient voltage change rate is iterated to obtain the transient overvoltage. According to the technical solution provided by the embodiments of the present disclosure, the transient overvoltage is determined based on the system operation parameters and the closed-loop transfer function of a DC line, the dynamic process of control parameter change caused by a control action of the control system after a fault occurs can be determined by the closed-loop transfer function of the DC line, whereby the transient overvoltage can be determined.