Elucidating the underlying mechanism of the cellular physiological activities at the molecular level is currently an important research topic in life sciences. The invention of the atomic force microscopy (AFM) provided new methods for acquiring new cognition about cellular chemical processes. With the use of AFM, the specific recognition interaction between CD20 antigen and rituximab antibody on B lymphoma cells was explored under near-physiological conditions. The high quality AFM images of B lymphoma cells were acquired and the CD20-rituximab complex binding force was measured by AFM single-molecule force spectroscopy (SMFS). The experimental results provide new insights for understanding the CD20-rituximab specific interaction and lay the foundation for the further investigation of the mechanism of rituximab.