Abstract: The use of Surface Plasmon Resonance (SPR) biosensors in analyzing biomolecular interactions is increasing significantly in recent years, since it has various advantages including real-time measurement of biomolecular interactions without labeling, high-throughput analysis of multiple proteins and the simple optical system for the device. Applications in life science include clinical assay, disease diagnosis, drug screening and so on. In this technique, one of the interacting partners is immobilized on a sensor chip and the binding of the other is followed by the increase in refractive index caused by the mass of bound species. Developments of related theories and technologies have accelerated performance of SPR biosensor greatly. For its high sensitivity, facility, expeditiousness and stable ability in weightlessness, SPR biosensor has a strong potential for on-line analyzing biochemical markers in astronauts' body fluids which are highly related to some kinds of diseases, and this is a practical method used as the health early alarm and medical care system for astronauts. This article is focused on the principle and advantages of SPR-based biosensor and its applications in life science. The future uses in space medicine are also discussed.