The invention discloses a finishing agent for bleaching and dyeing deoxygenation of cotton and linen. The finishing agent is prepared by mixing the following raw materials in parts by weight: 20 to 21parts of laccase, 15 to 19 parts of amylase, 10 to 15 parts of xylanase, 4 to 9 parts of pectin lyase, 0.2 to 0.4 part of glycine, and 12 to 15 parts of trehalose. The finishing agent is simple in source, natural, environmentally friendly, free from damaging fabrics, capable of modifying the cotton and linen to a certain extent, capable of enabling the cotton and linen fabric to have better dyeing effect, higher in dyeing rate, high in color fastness, and soft in hand feeling.