Abstract: Before the operation of the Kuanbang project,the Gaoling back-to-back DC（ hereinafter referred to as the Gaoling DC） delivery system had insufficient voltage support capability,DC blocking and thermal stability after AC line failure. After the operation of the Kuanbang project,Gaoling DC added an exchange channel to the main network of the northeast power grid. Power flow analysis,short-circuit ratio analysis,transient stability analysis,etc. are commonly used in the stability analysis of DC and its supporting projects. It adds static voltage stability analysis based on the forward analysis. Finally,the control strategies of pre-control DC power and returning DC power by the stabil-ity control device are proposed for the voltage stability problem after the fault of the near-area AC system in the Gaoling DC transmission terminal. This strategy can improve the stability of Gaoling DC and has been applied to ac-tual operation. The analytical methods and control strategies applied in this paper have certain applicability in the stability analysis of DC systems and their supporting projects.