Abstract: DC distribution system based on the flexible HVDC technology is the future trend of smart grid,which can provide better conditions for the flexible integration of DC loads and distributed generators（DGs）.But higher requirements for the system voltage stability are also needed.From a global stability point of view,the existence and uniqueness of power flow solutions for the DC distribution system are proved through the Banach fixed point theorem.A voltage stability analysis method based on the feasible solution of power flow is proposed to rapidly assess the voltage stability of DC distribution system and avoid the continuous power flow computation.Finally,the correctness and effectiveness of the proposed method are verified by simulation tests.