Oral examination requires comprehensive visual assessment of microcirculatory tissue bed as guidance for acquiring biopsy samples. Due to limited visual resolution and subjective evaluation criteria, physicians usually have limited access to the detailed state of diseases, consequently have difficulty in managing oral treatment at early stage. An endoscopic microscopy may help improve the detectable resolution on regional mucosa surface, but hardly reach deeper structures/vasculatures that reveals pathological origination and development. We propose a novel use of long ranging swept source optical coherence tomography (SS-OCT) system with unprecedented imaging field of view of 1600 mm2 for anatomic and microvascular imaging of human oral mucosa tissue in vivo. This system is further applied to identify and analyze oral mucosa lesions in situ without a need for invasive biopsy. Qualitative assessment of the structure characteristics (i.e. collagen fibrosis, volume of salivary glands, and tissue scattering) during wound healing delineates the anatomical lesion development accompanied with tissue inflammation. Quantitative assessment of the vasculature network (i.e. capillary loop density and vessel morphological orientations) reveals pathological and nutritional underpinnings of microcirculation for oral lesion recovery. Specifically, the progression of oral capillary angiogenesis, indicated by elevations in capillary loop density, occurs within 12 hours of disease onset and peaks at day 7 thereafter, which provide invaluable information for the time course of therapeutic treatment. Our demonstration shows potential movement of oral cavity OCT microangiography toward clinical translations.