Abstract: In order to improve the deficiencies of the existing scrambling algorithm effectively,a new image encryption algorithm based on dual scrambling about pixel position scrambling and RGB color space intensity value was proposed.Firstly,the rows and columns of 2D matrix would be mapped into 1D vector by making use of new proposed scrambling method based on pixel position.Then a set of pseudo sequence was generated by using the Logistic mapping,and it was ranked from small to large.The position that corresponding to each element was recorded by group sequence,which was called key stream.Finally,the corresponding pixel position of 1D vector was scrambled by index value which was formed by key stream.The encrypted image was obtained by 1D vector rearranged into a new 2D matrix.The experimental results showed that the proposed method had a large key space,and the scrambled image had a histogram distribution of white noise.The correlation of image pixel values was smaller.It greatly improved the ability to resist the illegal attack and increased the safety of encrypted image.