Oral cancer is a malignant tumor that arises from the tissues of the oral cavity. It is the eighth most common cancer worldwide, with a high mortality rate due to late-stage diagnosis. Traditional histological investigation is the gold standard for oral cancer diagnosis, but it is invasive and requires tissue biopsy. Liquid biopsy, a non-invasive approach, has emerged as a promising diagnostic technique for oral cancer in recent years. This technique examines tumors and their microenvironment by utilizing biomaterials found in bodily fluids such as blood, saliva, breast milk, and urine. The molecular cargo in liquid biopsy of malignant tumors include circulating tumor DNA(ctDNA), Exosomes, Circulating tumour cells (CTC), Micro RNA(miRNA) and cell free DNA. The use of liquid biopsy as a noninvasive method for early cancer detection, molecular profiling, treatment response monitoring, and detecting minimal residual disease holds great promise. This paper provides an overview of liquid biopsy as a diagnostic technique for oral cancer, focusing on its advantages, molecular candidates, and clinical applications.