Objective To simulate the microflow field environment between the anastomotic nail surface and intestinal wall tissue after implantation, and to study the effect of the hydrophobic surface on the flow rate of extracellular fluid and the fluid shear force on the wall, so as to regulate the bacterial adhesion through changes in the flow field. It provides a theoretical basis for the study of bacteriostatic surface of anastomotic nail. Methods The microstructure of shark skin was observed and a simplified two-dimensional movement model of bacteria in microflow field was established. By CFD numerical simulation, the movement of bacteria on smooth surface and micro-texture surface in static flow field and dynamic flow field were simulated, and 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 fluid shear force affecting bacterial adhesion was analyzed. Results The addition of biomimetic microtexture enhanced the flow rate of extracellular fluid in the microflow field, and the fluid had little viscous effect on bacteria in the static flow field. The fluid in the dynamic flow field has a stronger pushing effect on bacteria. The fluid shear force on the microtextured wall is greater because of the width of the pit in a certain range. Conclusion The bionic microtexture surface of nail can accelerate the flow rate of extracellular fluid, increase the fluid shear force of microtexture wall and bacteria, and have a certain influence on bacterial adhesion.