Abstract: Although the general quantum image encryption algorithm can achieve the encryption effect, it requires more qubits and higher computational complexity. To optimize this problem, this paper proposes a quantum color image encryption scheme based on bit-plane decomposition. First, a quantum representation model of color digital image (QRCI) with the information of bit plane order separately encoded was used to represent the image, and a qubit exchange operation was designed by quantum exchange gate and applied to the color image. The image pixels were scrambled. At the same time, the color channel exchange was performed on the image. Second, the sequence of bit planes was reversed to further enhance the scrambling effect. Afterwards, the hash value generated by secure hash algorithm 256(SHA-256) was used to determine the initial value of the chaotic system. Finally, the sequence generated by the chaotic system was used to diffuse the image, complete the encryption process, and form the encrypted image. Numerical analysis shows that compared with the previous encryption schemes, the proposed scheme greatly reduces the number of qubits required for color image storage, and has large key space and high sensitivity. Simulation results show that the scheme has good encryption effect and can resist most common attacks.