Objective:To study the content of total flavones in different parts of Mosla dianthera harvested in different seasons to pro-vide reference for the determination of optimal medicinal part and harvesting time of the plant. Methods:The total flavones content of M. dianthera was determined by TLC-UV. Results:The content of total flavones extracted from the plant in September was highest, and that in the leaves was much higher than that in the stems or the roots. Conclusion:It is advisable to harvest the aerial parts of M. dianthera in September.