A chaos immune evolutionary algorithm is presented to keep population's diversity, avoid local optimization and improve performance of evolutionary algorithm. To overcome redundancies, over-spread character of chaos sequence was used. To enlarge searching space and chaos initial value, sensitivity was used. At the same time, immune selection operator was used to adjust density, and vaccination was used to exert the advantage of individual. The experimental results show that the algorithm has good performance in the aspects of both convergence speed and the global convergence.