Adding an appropriate amount of aluminum sulfate can improve the dyeing effect of dye paper.Aluminum sulfate can improve the dyeing effect of anionic direct dyes more than cationic direct dyes; yellow dye can significantly increase the b value of paper, and the L value and a value will be different. The red dye can significantly increase the a value of the paper, and the L value and the b value can be reduced to varying degrees; the red dye reduces the L value to a greater extent than the yellow dye; the brown dye can increase the paper's a value , B value, but at the same time L value will be reduced; black dye can greatly reduce the L value of the paper, but at the same time a value, b value will be reduced to a certain extent; direct dyeing of bleached chemical pulp than Bleaching pulp has better dyeing effect; pulp with high beating degree is conducive to dyeing.