Abstract: Dynamic high pressure microfluidization was used for assistant extraction of polysaccharide from carp scales, and DPPH·,·O₂^-, ABTS⁺·,·OH scavenging power and Fe³⁺ reducing power were used to investigate the antioxidant activities of polysaccharide. The results indicated that the average particle size of carp scales powder which were treated with dynamic high pressure microfluidization was decreased from 499.80 nm to 192.57 nm. The yield of total polysaccharide was also greatly increased, the extraction yield was up to 7.81%, when the pressure of treatment was 130 MPa. With the increasing of pressure, DPPH·scavenging activity,·O₂^- scavenging activity, ABTS⁺·scavenging activity,·OH scavenging activity and Fe³⁺ reducing power were increasingly enhanced. The highest value of DPPH·scavenging activity,·O₂^- scavenging activity,·OH scavenging activity and Fe³⁺ reducing power were up to 86.04%, 61.23%, 90.59% and 0.64 (OD value), respectively, when the pressure of treatment was 110 MPa. The highest value of ABTS⁺·scavenging activity was up to 89.58%, when the pressure of treatment was 150 MPa. All treatments were significantly higher than the control group (P<0.05). The extraction yield and antioxidant activity of polysaccharide from carp scales was improved by dynamic high pressure microfluidization-assistant extraction. This study could provide the theoretical basis and technical support for the application of dynamic high pressure microfluidization in natural active polysaccharide extraction.