Biosensors have emerged as a promising tool for early detection of oral squamous cell carcinoma (OSCC) due to their rapid, sensitive, and specific detection of cancer biomarkers. Saliva is a non-invasive and easy-to-obtain biofluid that contains various biomarkers of OSCC, including carcinoembryonic antigen (CEA). In this study, an electrochemical biosensor for the detection of CEA in Saliva has been developed towards the diagnosis and early screening of OSCC. This biosensor utilized CEA-sensitive aptamer as sensitive elements. Fluorine-doped Tin Oxide (FTO) chip with surface modification of zinc oxide nanorod was employed as transducer. Electrochemical measurements were carried out to detect the responsive signals originated from the specific binding between aptamers and CEAs. The measurement results indicated that this biosensor was responsive to different concentrations of CEA ranging from 1 ng/mL to 80 ng/mL in a linear relationship. The limit of detection (LOD) was 0.75 ng/mL. This biosensor also showed very good specificity and regenerative capability. Stability testing over a 12-day period showed excellent performance of this biosensor. All the results demonstrated that this biosensor have great potential to be used for the detection of CEA in the saliva of OSCC patients. This biosensor provides a promising method for the rapid detection of CEA with convenience, which have great potential to be used as a new method for clinical diagnosis and early screening of OSCC.