The principle of Biosensor based on total internal reflection of imaging ellipsometry, methodology, experimental setup and functions is reviewed, especially the settings of optimization condition, which has key importance for the biosensor sensitivity. The biosensor may be used for high throughput bio-interaction process detection between nucleic acid and protein, protein and protein, ligand and receptor, and even virus and ligand, etc. Some biomedical applications and an extension application of biological oxygen demand (BOD) detection are demonstrated.