Abstract: This paper discusses on image encryption based on three dimension Rössler system，which not only rotates the position of pixels but also exchanges the pairs of pixels depending on any two dimensions of Rössler chaotic sequences，and changes the gray value of pixel depending on the third dimension of Rössler chaotic sequences.The algorithm has Rössler key and scrambling key，which increases keys space and makes keys’ management more convenient.The algorithm provides good security，high encryption efficiency，and can be easily used in image encryption.Compared with space domain compound method realized by Chebyshev mapping，the algorithm is faster in encryption and has larger keys space.