An outdoor shading device includes a supporting frame, a shading awning supported by the supporting frame to define a shading area underneath the shading awning, and a solar power system. The solar power system includes a solar collecting unit having a solar collecting surface overlapped on the shading awning for solar energy collection, and a power storage supported at the supporting frame to electrically connect to the solar collecting unit, wherein when the shading awning is orientated for providing shade from the sun, the solar collecting surface of the solar collecting unit is aligned with the direction of the sun to maximize the solar energy collection, such that after the solar energy is collected, the solar collecting unit converts the solar energy into electrical energy and stored in the power storage.