On the basis of chaos system and Henon map, a new fast image encryption algorithm is presented. Two-dimensional reversible nonlinear Henon map that is dealt with mould operation is utilized to circularly iterate gray value of pixels by chain type. In each step, iterated times and parameters of Henon map are sequentially set as values of a chaotic sequence which is generated by one-dimensional chaotic map. In this algorithm the computational speed is fast due to simple design and it is accurate to decipher cipher text. Especially，it solves difficult problem of failure in deciphering because of limited precision and different precision in different computers generally existing in algorithms based on chaos or nonlinear map. The algorithm avoids inherent defects and inadequateness of cryptological intensity of other algorithms adopting permutation transform and thus has super security.