The invention relates to a dyeing technique for polyester cotton or polyester viscose/chinlon/spandex multi-component fabric by a one-bath two-step process and belongs to the technical field of textile dyeing process. The dyeing technical includes the following process steps: putting the to-be-dyed polyester cotton or polyester viscose/chinlon/spandex multi-component fabric into a dye vat, feeding water to the specified water quantity, increasing the temperature to 30+/-5 DEG C, sequentially adding salt or anhydrous sodium sulphate and levelling agent prior to continuing operation for 5-10 minutes, then adding reactive dye, disperse dye, weak acid dye or neutral dye for operation for 5-10 minutes prior to increasing the temperature to 60+/-2 DEG C at the rate of 0.5-1 DEG C/min, then adding sodium carbonate, keeping at the temperature for 30-50 minutes prior to neutralizing the sodium carbonate with dyeing acid, slowly regulating the pH value to 5.5-6.5, uniformly rotating prior to increasing the temperature to 130+/-2 DEG C at the rate of 1-1.5 DEG C/min, keeping at the temperature for 40-60 minutes, and then cooling and discharging water prior to aftertreatment. By the technique, the process of the dyeing technique can be shortened effectively, time for dyeing is reduced, production efficiency is improved, steam and water consumption is reduced, pollution discharge is reduced, and dyeing cost is lowered.