The invention provides an SPR measuring method and a measuring system thereof. According to the measuring method, first, a linear-polarized coherent broadband pulsed light beam is incident onto a surface of a sample under detection of a SPR sensing device to cause reflection; next, a time-domain monotonous chirp is performed on the incident coherent broadband pulsed light and/or the SPR reflected light; finally, the time-domain monotonically chirped SPR reflected light beam is detected, and information of the SPR effect is obtained according to the detected signal. According to the invention, the spectrum detection method used in conventional slow wavelength interrogation is converted into the high-speed real-time detection of time-domain pulse shape signals. Thus, the procedure of the SPR reaction may be monitored closely, and dynamical curves with very high time resolution may be obtained, in that case, fast biochemical reaction procedures may be monitored. As each part of the measuring system may remain fixed during the measurement, a compact, miniature and portable system may be realized. The interrogation part of the sensing system is easy-to-realize, of low cost and compatible with various SPR devices and components.