Abstract: With the development of radio technology, radio frequency interference (RFI) is increasingly affecting radio astronomical observations, especially the impact of periodic RFI on astronomical observations becoming more significant. This article focuses on broadband high time-resolution spectral data and proposes a statistical method for periodic RFI in broadband spectrum sequences. The method involves threshold calculation, noise channel filtering, fast Fourier transform, period calculation, channel merging, source analysis, and template library establishment. This method is applied to the Nan Shan 26 m Radio Telescope (NSRT) of Xinjiang Astronomical Observatory using data from the pulsar observation terminal, effectively detecting and proposing the periodic RFI spectrum sequence, providing data support for further mitigation of electromagnetic interference.