The transient rated calculation of AC filters in converter station is used to choose the suitable arresters for protecting the reactors and resistors in filter, also for determining the insulation levels and transient impulse currents of the devices in AC filters. Taking ±800 kV Jinping Sunan UHV DC Power Transmission Project as an example, the calculation methods of transient rating for AC filters are introduced in detail, including the schemes of arrester choosing, the determination principle of insulation levels for AC filters components (capacitance, reactance, resistance, etc.), as well as the calculation method of transient voltages and currents for other important parameters determination. The methods and parameters introduced are the important references for equipment selection, such as capacitors, reactors, resistors, arresters and current transformers in AC filters in HVDC power transmission project.