Maximum entropy spectral analysis is applied to historic earthquake data from the Bohai Sea and its adjacent areas to statistically analyze and identify the periodic characteristics of seismic activity in the region. The results indicate that seismic activity in this area exhibits quasi-periodic behavior,with a dominant period ranging from 29a to 36a. Since 1517 AD,the region can be divided into 16 seismic periods,with the current period identified as a mid-term phase of seismic quiescence. The average seismicity level is estimated through statistical analysis of earthquake frequencies within each seismic period,providing valuable insights into the long-term patterns of seismic activity in the Bohai Sea region.