Object To isolate fetal nucleated red blood cells (fNRBCs) from whole maternal peripheral blood effectively by designing a circular microfluidic chip. Method In this paper, a microfluidic chip is reported by utilizing the margination in blood flow and the specific adhesion characteristics of immuno-agent anti-CD147. With the whole umbilical cord blood, we study the effects of different shear forces on the enrichment of fNRBCs with the help of immunofluorescence counting. Results Increasing shear rate in microfluidic chip can improve the capturing of fNRBCs. The number of the captured cells increases at first, and then decreases with the increase of shear rate of blood flow. Conclusions Our method offers effective method to isolate fNRBCs from the whole blood. This research provides an experimental reference for the non-invasive prenatal diagnosis research and the exploration of the mechanism of fetal cell migration.