The invention discloses a portable low-residue blood-return-proof pre-flushing type disinfection syringe. The syringe comprises a cap (1), a jacket (2), flushing liquid (3), a plunger (4), a core rod (5) and a disinfection connection cap (6). The flushing liquid (3) is prefilled in the syringe, and when the core rod (5) pushes the plunger (4) to the bottom end of the jacket (2), a pin (42) of the plunger (4) is inserted into a 6:100 inner hole (22) of the jacket (2) to realize taper interference fit. In clinical application of the portable low-residue blood-return-proof pre-flushing type disinfection syringe, tubes of indwelling needles, PICCs (peripherally inserted central catheters), CVCs (central venous catheters), implantable venous access ports and the like of patients can be directly flushed and sealed without extraction, and medicine residues in the pre-flushing type syringe can be reduced to the greatest extent, so that liquid medicine waste is reduced, liquid medicine utilization rate is increased, and the syringe is especially high in value for expensive medicines or medicines high in dosage requirement. The portable low-residue blood-return-proof pre-flushing type disinfection syringe has the advantages of novel structural conception, economy, practicality, convenience for medical workers to operate, simplification of normal operation process, increase of the liquid medicine utilization rate and convenience in clinical promotion and application.