The present invention provides a surface plasmon resonance (SPR) detection system. This system utilizes a detection light path to form a detection image containing incident angle information and wavelength information. During testing, full-spectrum scan is performed first to obtain a resonance wavelength of a sample. Then, partial-spectrum scanning is performed by continuously tracking the resonance wavelength, and the number of scanning points in each scanning cycle is controlled according to specific situation to shorten the scanning time, thereby obtaining the resonance wavelength of the sample in real time. When the refractive index of the sample changes, the corresponding resonance wavelength changes as well; by obtaining the change of the resonance wavelength, variation of the reflective index of the sample is calculated, which is rapid SPR detection of wavelength modulation.