Three-axis Ultraviolet Optical Sensor (UVOS) is designed. The observation problem for a very wide field of view is solved in the orbit for near earth. By the irregular optical system that is reflecting arrays and combined optical system,the circular wide field of view is divided into 8 sub-fields. UVOS provides both three-axis attitude and autonomous navigation data by utilizing image-overlap and image-processing. Calibration precision for UVOS is under yaw angle 0.05°,pitch angle 0.05°and roll angle 0.05°. Engineering Model is finished. By means of observing star experiment and star simulator experiment,UVOS can measure 5 magnitudes. UVOS is one of the important sensors for space vehicles of deep space exploration