Capacitive biosensors are increasingly popular in biomedical analyses. In order to satisfy the requirements in medical diagnostics, such as high sensitivity and quick response, this paper presents a developed capacitive biosensor based on the surface stress to detect classical swine fever virus (CSFV) antigens. The developed biosensor is composed of a substrate layer and a sensitive layer. The sensitive layer is functioned with antibodies for CSFV antigens. Once the CSFV antigens bind to the antibodies, the increased surface stress will result in convex deformation, converting to capacitance changes. Scanning electron microscope (SEM) and atomic force microscope (AFM) are two methods used to monitor the surface changes. The experimental results demonstrate that the sensing electrode modification process is successful, and the surface stress induced by the binding of antibodies and CSFV antigens can cause variations of capacitance. In conclusion, the developed capacitive biosensor can be used to detect the CSFV antigens, and it has the potential to detect other antigens in the future. Display Omitted A capacitive biosensor based on surface stress can be used to detect CSFV antigens.The surface stress induced by the binding of antibodies and CSFV antigens can cause variations of capacitance.The changes of biosensor are corresponding to the theoretical analysis.