The invention provides a dyeing technology of chemical fibers and relates to the field of dyeing of chemical fibers. A dyed chemical fiber product can be obtained through steps of pretreatment, purification treatment, presetting, dyeing, reduction and soaping, fixation and smooth setting. Oil solutions, stained oil dirt, dust, pigments and the like added in chemical fiber spinning and weaving processes are removed during pretreatment, the purification treatment is added to the technology, staged heating is adopted in the dyeing process, a leveling agent and a penetrating agent are added, a fixation foam liquid is sprayed for fixation, so that the dye utilization rate in the production process is high, the produced chemical fibers have full color, high color fastness and good uniformity, meanwhile, energy consumption is low, and little wastewater is produced.