The ability to recognize humans by computer vision is a very important task, with many potential applications. In this thesis, we present a new method for an automated marker-less system to describe, analyze and recognize the human gait motion. The automated system consists of four stages: i) detection and extraction of the moving human body and its contour from image sequences; ii) extraction of human gait signatures based on topological analysis guided by known anatomical knowledge; iii) description of gait parameters by statistical analysis of the gait signatures; and iv) feature extraction and recognition of human gait. The gait signature is represented by a sequential set of 2D stick figures during one gait cycle. A grammatical structure with constraints of the gait sequences has been developed to improve the robustness of the gait signature, together with a new method of step symmetry. In the gait signature, the motion parameters based on biomechanical studies are calculated for characterizing the human gait. The inherent periodicity in gait motion is detected by graphical methods and analyzed by statistical approaches. Also, the periodic gait modern is modelled by interpolation of trigonometric-polynomials. In addition, the features based on motion parameters are extracted from the sequence of gait signatures. Then, a k-nearest neighbour classifier and an enhanced back-propagation algorithm is employed to recognize the gait. In experiments, the proposed methods have been successfully demonstrated on the largest available database. The gait signature is a very effective and well-defined representation method for analyzing the gait motion. It can be applied to other areas such as biomechanical and clinical applications.