The invention provides a face motion tracking method, a face motion tracking system and a method for enhancing reality. The face motion tracking method comprises the following steps of: 1) extracting face characteristic points and face contour characteristics of a video image; 2) determining the number of the face characteristic points; and 3) under the condition that the number of the face characteristic points is greater than a preset threshold value, performing motion tracking on faces in the video images by using the face characteristic points and a three-dimensional model, and under the condition that the number of the face characteristic points is smaller than or equal to the preset threshold value, performing the motion tracking by using the face contour characteristics. By the method, head motions can be accurately tracked to prevent determined face characteristic points from being lost; moreover, during real-time tracking, only a few face motion data is transmitted by a communication network, so the method is suitable for various mobile phone platforms, has low requirements on hardware conditions, and can be applied to video call interaction to improve the interest and the interaction of a call.