The total flavonoids content in different parts (leaf, stem, root and rhizome) of two-year-old and eight-year-old cultivated Glycyrrhiza glabra L. collected in April, June, August and October were determined by UV-visible spectrophotometry method. The result shows that the average content of total flavonoids of two-year-old and eight-year-old plants reaches the highest in June with the average content of 35. 55 and 39. 97 mg· g^-1 , respectively. According to the average content of total flavonids in different parts of two ages plants, the order from the highest to the lowest is basically same, all appear that upper leaf is the highest, middle leaf is the second, different under-ground parts are middle, and lower stem is the lowest. The comprehensive analysis results indicate that there are no obvious differences in change regularity of total flavonoids content in G. glabra with different cultivated ages. Two-year-old cultivated G. glabra could be harvested, the optimal harvesting time is October, and the harvesting parts are leaf and under-ground part.