Abstract: To study the factors affecting the scaling of freshwater fish, carp, grass carp, crucian carp and silver carp were taken as research objects, and TMS-PRO type texture analyzer was used to measure the bio-adhesion force between fish scales and their bodies. Three factors that influence on the bio-adhesion force of fish scale, including the position of fish scales, the loading rate and the time of death, were studied. Then the number of scales in unit area and friction angles of freshwater fishes were measured, and scaling experiments was conducted. The relationship between the bio-adhesion forces of fish scales and the effect of scaling were analyzed and verified. The results show that scaling of freshwater fish will be more difficult when the bio-adhesion force is bigger. This study can provide a reference for design of scaling device for freshwater fish.