The selfdeflection characteristic of dark photovoltaic spatial solitons in onedimensional stable closed circuit is investigated by taking diffusion effects into account by use of numerical method. The results show that dark photovoltaic spatial soliton possesses a selfdeflection process in the direction of the crystal’s axis during propagation and the center of the dark solitary beam moves on a parabolic trajectory. The selfbending distance of the dark solitary beam increases monotonously with the photovoltaic field and the solition input intensity. The self-deflection of dark photovoltaic solitons is very different from that of bright ones.