When small tail-sitter aircraft makes a high maneuvering flight,its attitude will change greatly.The traditional transformation algorithms from quaternion to Euler angle cant calculate out all its attitude angles.Thus we made some improvements to the traditional algorithms,and proposed an all-attitude conversion algorithm adaptable for Euler angle from -180° to 180°.This algorithm avoids the concussion of traditional algorithms at transform boundary under disturbance,and can ensure the continuity of attitude changing.Simulation result indicates that the proposed algorithm is feasible.