Objective To simulate the microflow field environment between the anastomotic nail surface and intestinal wall tissue after implantation and to study the effect of hydrophobic surfaces on the flow rate of extracellular fluid and the fluid shear force on the wall to regulate bacterial adhesion through changes in the flow field. Methods The microstructure of shark skin was observed, and a simplified two-dimensional (2D) movement model of bacteria in a microflow field was established. Using computational fluid dynamics (CFD) numerical simulation, the movement of bacteria on a smooth surface and micro-textured surface in a static and dynamic flow field were simulated. The flow field characteristics around bacteria and the magnitude of fluid shear force under the two surface environments were compared, and the internal mechanism of the fluid shear force affecting bacterial adhesion was analyzed. Results The addition of the biomimetic microtexture enhanced the flow rate of the extracellular fluid in the microflow field, and the fluid had little viscous effect on the bacteria in the static flow field. The fluid in the dynamic flow field had a stronger pushing effect on the bacteria. The fluid shear force on the microtextured wall increased when the pit width was within a specific range. Conclusions The bionic micro-textured surface of the anastomotic nail can accelerate the flow rate of extracellular fluid, increase the fluid shear force of micro-textured walls and bacteria, and influence bacterial adhesion. These results provide a theoretical basis for studying bacteriostatic surfaces of anastomotic nails.