Abstract: A fast and accurate ray-target face incident angle measurement algorithm is proposed to meet the requirement of practical ray-target face incident angle measurement mission. Since the geometry distribution relationship among the advanced-set feature points changes along with the pose transformation, ray-target face incident angle could be measured in a non-contact way. On the basis of drawing target face identification points, ray-target face incident angles are calculated using optical sensor internal parameters. Both simulations and experiments are conducted to prove the effectiveness and practicability of the proposed algorithm. The results confirm the high stability and reliability of the proposed method.