The invention discloses a polyester-cotton microcapsule disperse reactive dye one-bath dyeing technology. The technology comprises the steps of: S1, polyester dyeing: dipping a to-be-dyed polyester-cotton fabric in a dye solution containing microcapsule disperse dye, conducting heat preservation at 65-75DEG C, then performing heat preservation at 110-130DEG C, and carrying out cooling to 30-40DEG C, using chitosan to serve as the carrier of the disperse dye, and then conducting crosslinking curing; S2. cotton dyeing: adding a quaternary ammonium salt cationic etherifying agent, carrying out stirring reaction, then adding a reactive dye, performing heat preservation at 55-65DEG C, adding an organic solvent, conducting heat preservation at 70-90DEG C, then adding organic amine and sodium carbonate, and performing heat preservation at 60-100DEG C; and S3, aftertreatment: performing cooling to room temperature, and then carrying out primary washing, soaping and after-washing. The polyester-cotton microcapsule disperse reactive dye one-bath dyeing technology provided by the invention has the advantages of simple process, little pollution, wide dye applicability, uniform coloring, high color fixation rate and good level-dyeing properties.