Abstract: Chaotic sequences have several good properties including the ease of their generation, their sensitive dependence on initial condition and noise like. In this paper, we discussed an image encryption arithmetic based on chaotic sequences. We generate the real number value chaotic sequences by using the key value and disperse them into symbol matrix and transformation matrix. We implement the image encryption algorithm based on the technique of image scrambling transformation in space or frequency domain. Our algorithm provides good security. Experimental results are satisfactory.