This paper proposes a nonlinear coupled two-dimensional generalized Feigenbaum chaotic mapping，by using bifurcation graphics, we studied the complex nonlinear dynamic activities of two-dimensional formula. By using the coupled two-dimensional generalized Feigenbaum chaotic mapping a chaotic sequence is generated, then the chaotic sequence is optimized into secret key stream, and scrambling method is introduced in this encryption algorithm, this changes values of pixels. The results of experiment simulation show that the extremely sensitive to the key , the choice of chaotic sequence depends on the plaintext sensitively that enhances the ability of resisting the chosen plaintext attack, the information entropy of the cipher image is 7.99694974187328, it is very close to the ideal value 8,the encrypted image has random-like distribution behavior of grey values, the correlation between the encrypted image and the plain image is very small, the adjacent pixels have zero co-correlat ion properties, the algorithm has the advantages of large key space and high speed of encryption.