To address the challenges posed by large-scale changes of the sending grid tide and the voltage disturbance in converter buses caused by random fluctuation of wind power, which further leads to additional actions of the discrete equipment in the converter station, this paper proposes a coordinated secondary voltage control method for AC-DC systems that consider the randomness of wind power. Firstly, the degree of wind power fluctuation is quantified by defining the relative deviation of power, and characteristic time periods of wind power fluctuation which cannot be ignored in the secondary voltage control are identified. Next, the k-means clustering method is employed to obtain typical scenarios of wind power output during these characteristic time periods. Finally, the probabilistic scenario method is used to represent the randomness of wind power, and the uncertainty optimization problem is solved using the chance constraint method. The effectiveness of the proposed method is validated through simulations conducted on a modified IEEE39 node arithmetic system.