In this study, tin oxide (SnO2) thin films are sputtered onto a carbon electrode to develop a SnO2/carbon pH sensor. The SnO2/carbon pH sensor shows pH sensitivity in the range of pH 2-12, with sensitivity of 56.35 mV/pH. Moreover, the electron mediator and enzyme are coimmobilized onto the surface of the base electrode, SnO2/carbon pH sensor, to fabricate a SnO2/carbon dual-mode glucose biosensor. The operation mode of the dual-mode glucose biosensor, amperometric or potentiometric mode, is determined via the mode selection in the dual-mode circuit. The SnO2/carbon dual-mode glucose biosensor demonstrates the detection limit up to 360 mg/dL. Additionally, to realize the small dimension and low-cost advantages for portable and home-care purposes, a homemade dual-mode circuit is designed for detecting amperometric and potentiometric signals. Hence, the SnO2/carbon dual-mode glucose biosensor and pH sensor are successfully fabricated on the SnO2/carbon electrode and integrated into one system by the dual-mode circuit.