The invention discloses a dyeing method for a knitting fabric. The dyeing method comprises the following steps: 1) sequentially adding dibutyl phthalate, glycollic acid, hydroxy ethyl cellulose, sodium acetate and a wood dye into deionized water in a dye vat, uniformly stirring all the raw materials, and heating the mixture to 55 DEG C; 2) then sequentially feeding 1,3,5-triazine-2,4,6-trithiol trisodium salt, sulfated castor oil, diethylenetriamine and aluminium oxide powder, continuously stirring all the ingredients until fully and uniformly mixing all the ingredients, and heating the mixture to 65 DEG C; 3) soaking the fabric in the dye vat for 25 minutes; 4) drying the soaked fabric at a temperature of 80 DEG C; 5) immerging the dried fabric in clear water, and rinsing the fabric for 25 minutes; and 6) taking out the rinsed fabric, and naturally airing the fabric. The fabric dyed by the dyeing method has excellent color fastness, and is good in dyeing uniformity and free from dyeing defect.