Objective:To determine the content of total flavonoids of Agrimonia pilosa Ledeb.at different harvest time,for selecting its best harvest time.Methods:Ultraviolet spectrophotometry was used for the determination of total flavonoids of Agrimonia pilosa Ledeb.at different harvest time in Luzhou.Results:The content of total flavonoids could be detected by ultraviolet spectrophotometry.Total flavonoids had good linearity in the range of 0.0055～0.088mg·ml^-1（r=0.9997）,the average recovery was 98.15%,and RSD was 1.18%.The content of total flavonoids in Agrimonia pilosa Ledeb.in Luzhou was 10.77%in June,and 12.38%in July,much higher than in any other month.Conclusions:This experiment establishes a method using ultraviolet spectrophotometry to detect the content of total flavonoids,it is simple,rapid,sensitive,with high precision,high accuracy and good repeatability and recovery.The reasonable harvest time of Agrimonia pilosa Ledeb.in Luzhou is June and July.