In order to obtain a larger color gamut in the green region and broader gamut coverage with Rec. 2020, 532 nm laser light was adopted as the fourth primary. The color gamut volume, gamut coverage with Rec. 2020, gamut enhancement in the green region, and gamut coverage in the yellow region of RGGB(red, green, green, blue) wavelength set 660 nm,532 nm,520 nm,465 nm was simulated and analyzed in CIEL*a*b* uniform color space. The result shows that the maximum color gamut volume is 2218900, the maximum gamut coverage with Rec. 2020 standard is 97.51%, and the maximum gamut enhancement in the yellow region and green region is 29.75% and 9.58%, respectively. This RGGB system has excellent performance when compared with RGB three-primary system and RGBY four-primary system, and the luminance ratio can be adjusted according to the actual requirements. This research provides another feasible idea for the construction of a four-primary color display system.