Evolutionary algorithm is a kind of according to the selection and evolution of biological evolution model and the evolution of a kind of random search technology. Evolutionary algorithm is a blend of genetics, and cell biology evolution, therefore has a comparatively complete theoretical basis. Evolutionary algorithm has a good robustness, parallelism and flexible structure and so on. At present, widely used in path planning, feature selection, image processing, etc. This paper introduces the four parts, first is the basic theory of algorithm and the characteristics of the general framework, algorithm research, mathematical model and algorithm of improvement.