Surface plasmon resonance (SPR) has recently been one of the powerful tools to study surface or interface in the field of biology, since it was applied to biochip array. The advantage of SPR is that the binding or adsorption of a small amount of sample to the interface can be sensitively detected without labeling a fluorescent probe. Surface plasmon-field enhanced fluorescence spectroscopy (SPFS) is based on SPR principle in which SPR field is used as an excited field for fluorescent probe. Therefore, it is available to the interface detection due to the advantages of higher sensitivity and lower background (noise). The author introduces here results of the research projects studied by SPR-SPFS, i.e., affinity of double strands in DNA-DNA hybridization and formation process of substrate supported phospholipid membranes.