In order to solve the problems of low test speed, inaccurate analysis of transient signal detection and poor real-time performance of traditional spectrum analysis systems, a Frequency Mask Triggering(FMT) technology combined with reconfigurable computing is proposed to achieve ultra-high speed data capture, detection and analysis. The digital fluorescent display technology is adopted to make the displayed signal spectrum more real-time and intuitive. The measured results show that the system has improved the accuracy of signal analysis within the acceptable performance loss range. The reconfigurable calculation makes the system run more efficiently, reduces the energy consumption, and enables the system to achieve real-time and accurate analysis on the transient signals and complex signals even under large bandwidth conditions.