The invention discloses a dyeing process of a high-grade environment-friendly clothing flannel fabric. The dyeing process comprises gray fabric which can be dyed after being unwound. According to the dyeing process, the gray fabric is pre-shaped, so that the molecular structure of the gray fabric is stable, the water content of the fabric is uniform, the fabric surface is flat, creases are eliminated, the quality of the dyed gray fabric is better, the obtained flannel fabric is more high-grade and environment-friendly, the fabric is soaped after being dyed, dye molecules on fibers can be associated to form microcrystals, thus the color of the fabric is bright and full, the solarization and chlorine bleaching fastness is improved, the fabric is softened, the surface of the fabric is smooth, the internal friction force of the fabric is reduced, the rebound resilience is improved, and creases and scratches generated in subsequent processing of the fabric are avoided; the fabric is dehydrated and shaped, the whole crack degree of fiber molecules and the compactness of the molecular structures are improved, and the dimensional stability of the fabric can be improved.