<p>Holographic 3D display technology, widely considered the ultimate solution for real 3D display, has broad applications in fields including advertisement, industrial manufacturing and military. However, it is difficult to simultaneously realize color holographic 3D display with wide viewing angle and high brightness required for an immersive visual experience. Here, a novel holographic 3D display system based on a customized achromatic liquid crystal grating and a phase-only spatial light modulator is proposed. Thanks to the secondary diffraction performed by the achromatic liquid crystal grating, nine secondary diffraction images of red, green and blue channels overlap in space in time sequence. Additionally, a high brightness hologram encoding method is developed, which introduces a frequency loss function with dynamic weights to ensure that differences of all frequency components in the frequency domain can be learned. The proposed method dramatically enhances light energy utilization by a factor of five, resulting in significantly brighter reconstructed images while substantially attenuating background noise in non-target regions. This groundbreaking system, achieving a remarkable ~ 65° wide viewing angle with good image quality and high brightness, represents a significant advancement in holographic technology, offering a comprehensive solution for wide-viewing-angle, high-brightness, color 3D displays with potential applications across diverse technological domains.</p>