The invention provides a calculation method and device of active power of an alternating-current network-side grid-connected point of a converter station. The method comprises the steps that 1, a direct-current-side power value of the converter station is calculated; 2, the direct-current-side power value of the converter station is utilized to update the active power of the alternating-current network-side grid-connected point of the converter station; and 3, whether the active power of the alternating-current network-side grid-connected point of the converter station meets a convergence condition or not is judged, if yes, the updated active power of the alternating-current network-side grid-connected point of the converter station is output, or otherwise the active power of the alternating-current network-side grid-connected point of the converter station is updated, and the step 1 is returned to. According to the technical scheme, through analysis of a modulation outlet of the converter station and the electrical quantity at the alternating-current network side, a direct-current power flow calculation and alternating-current calculation alternate iterative calculation method isadopted, calculation of the active power of the alternating-current network-side grid-connected point of the converter station is realized, an AC/DC power distribution network power flow algorithm iscompleted, and therefore beneficial guidance is provided for efficient and safe running of an AC/DC hybrid power distribution network.