In order to further improve the security and efficiency of quantum image encryption, a three-layer encryption scheme for quantum color images based on 6D hyperchaos is proposed for the improved quantum representation model. The sequences generated by the 6D hyperchaotic system are applied to each layer of image encryption as keys. First, the quantum Fibonacci matrix is used to scramble the pixel value positions of the image to achieve the spatial scrambling of the quantum image; then, the position exchange of red, green, and blue channels and the bit-level cycle shift of pixel value are carried out alternately to realize the bit-level scrambling of quantum images; Finally, the XOR operation is performed on the quantum image whose position has been scrambled to realize the bit-level diffusion of the quantum image and obtain the final encrypted image. Simulation results show that the encryption algorithm is highly sensitive to the initial key, and the pixel values of the encrypted image are evenly distributed. In addition, quantum circuits are designed to implement the image encryption steps of each layer.