There is growing interest in the whole saliva as a diagnostic fluid because of the relatively simple and non-invasive collection. Research on salivary proteomic and genomic has greatly facilitated the diagnosis and therapy of oral diseases, also revealed the molecular mechanism of the diseases. Saliva-derived exosome as a new source, with various molecular constituents of their cells of origin, including proteins, mRNA and miRNA might serve as potential biomarker. This article reviews the biological properties of saliva exosome, its separation and other aspects associated with disease.