Abstract: Metasequoia glyptostroboides abounds with flavonoids. Total flavonoids in the leaves of M. glyptostroboides from three sampled trees in different seasons were extracted by method of supersonic extraction and their contents were determined by means of UV-Vision spectrometry with rutin as a standard. The contents range from 0.970% to 1.556%, which the peak is in the end of June. Natural change rule of total flavonoids' content along with the change of seasons was roughly disclosed.