Abstract: In recent years, with the advancement of lab-grown diamond technology, production scales have been continuously expanding. Driven by market demand for colored diamonds, there is an urgent need to develop high-quality color modification techniques. Our research team has implemented a novel surface coating coloring process on lab-grown diamonds using physical vapor deposition (PVD) magnetron sputtering technology, referencing successful synthetic gemstone coating modification techniques. Through precise process control, we achieved accurate color preparation, enabling moissanite to attain refined chromaticity values in "colored" gemstones as measured by CIE colour index. This approach achieves a colour difference ΔE between two different colours as low as 2.4. To address the unique characteristics of lab-grown diamonds, this study conducted microscopic photography, UV-Vis spectrophotometry, and micro infrared spectroscopy analyses on the "colored" diamonds. Controlled heating experiments and corrosion resistance tests were also performed to evaluate colour stability. Comparative investigations revealed that magnetron sputtering-coated lab-grown diamonds exhibit excellent high-temperature resistance, corrosion resistance, and durability. This research provides valuable references for advancing coating technology development and lays the foundation for practical applications of "colored" lab-grown diamonds.