The additivily of chaotic time series is proven theoretically. The result of our computer simulation illustrates that the new chaotic time series, praduced by combining several chaotic time series. Canbave fractal attractors, and is sensitive to the initial states, and predictable in short-term prediction. Also, two different trajectories well depart exponentially with time. Therefore,these new series are chaotic time series. We can say that chaos has characteristic of addition. The characteristic that chaotic time series can be integrated is not only important in theory, but also important in practice. It is a theoretical base to research hopping frequency codes of multi-radio-station.