Based on the three-channel numerical control rotor spinning machine, this paper aims to develop a spinning technology that can control the yarn color in the full-color gamut. A seven primary color fiber grid blending mode and full-color gamut grid color mixture model containing 601 grid points were constructed. The mechanism of three-channel rotor spinning with coordinated regulation of three-channel feeding speed ratio, primary color fibers blending ratio and yarn color was constructed. The process theory of spinning the full-color gamut mixed color yarn based on the full-color gamut grid color mixture model formed by the grid blending of seven primary color fibers was developed. On this basis, 55 trial samples were selected from the full-color gamut grid color mixture model for spinning and knitting into fabric, and the evenness, strength, hairiness and other indicators of the yarn were tested.