To confirm the pilot fatigue, most of methods are carried out through the analysis of eye states. A new algorithm of eye states recognition was proposed based on combining of radial symmetry transform and circular Hough transform. Firstly, the eye states were recognized based on radial symmetry characteristic of iris when eyes were open, and then for the images which were not recognized only by radial symmetry transform, the center and radius of iris were determined by circular Hough transform. Comparing the position of iris center located by circular Hough transform and the iris center located by radial symmetry transform eye states recognition in these images could be achieved. This method has been applied to pilot fatigue flight video processing and experimental results show that the proposed algorithm achieved a relatively better eye state recognition result. Average success rate of the proposed method is 94.9%, which meets the needs of application requirements of pilot fatigue monitoring.