The effect of electrode force on the weld quality of resistance spot welding monitored using electrode displacement was experimentally studied in this article. The electrode displacement was detected by the grating displacement sensor, and the maximal electrode displacement was obtained by the measurement system. The weld quality was evaluated by the tensile-shear strength of spot welds. Groups of spot welding experiments were performed under different electrode pressure, and the relationship of the maximal electrode displacement and tensile-shear strength in weld lobe was analyzed. The results showed that the relationship between electrode displacement and weld quality is not constant when the electrode force changed.