The label- free, real- time and high sensitivity bio- detection serves as an important technology in analytical biology field. Biosensor model is constructed with optical waveguide mode theory, and a miniaturized biological sensing detection system is designed based on MEMS micro-mirror. Its dynamic response characteristic is tested and analyzed. By calculating and simulating, the relationship between sensitivity and thickness of waveguide and effective refractive index is obtained. Glucose solution is detected in TE mode and TM mode, experimental result shows that a well linear relationship between concentration of the glucose solution and incidence angle is presented, and the precision can reach 5 ng/mL. Compared with the traditional immunological detection methods, it has a relatively high sensitivity. Due to the small system and simple structure and label-free, it can realize the in-situ detection to avoid damaging the activity of protein, and it is a label-free optical detection method with great potential.