Optical coherence tomography angiography (OCTA) is an important tool for investigating microvascular networks and microcirculation in living tissue. In this study, OCTA was employed for noninvasive in vivo monitoring and assessment of inflammation induced by bacteria in a mouse ear model. Imaging results demonstrated that OCTA can monitor changes in microvascular density and morphology of blood vessels caused by immunovascular responses during the inflammatory process with a high degree of resolution and sensitivity. Distinctly enhanced OCT signals from the mouse ear were observed following bacterial infection owing to an influx of red blood cells caused by the bacteria. A highly dense microvascular network noted in the palms of healthy subjects by OCTA, demonstrates the feasibility of OCTA for the clinical evaluation of inflammation. This method can improve the understanding of the pathological mechanisms of inflammation and can be useful in the clinical evaluation of inflammation.