This paper adopts reactive disperse bright-red KR-2B to dye wool skeins in supercritical CO2 dyeing equipment. The influencing factors are analyzed by measuring the surface depth of dyed wool skeins, including time, temperature and pressure, and the optimal dyeing parameters are as following: time 60min, temperature 120°C, pressure 24 MPa. Then we adopt the scanning electron microscope (SEM) and the infrared spectrum (FTIR) to observe the apparent shape and structure before dyeing and after dyeing. The results indicate that the global dye structure divide and the dyestuffs have good fixation on the wool skeins.