Ailanthus excelsa Roxb is useful in preventing Asthma, Bronchitis, Washing wounds, skin eruptions, Anthelmintic, Gout, Cholera and Dysentery. So it has medicinal important plant species. The present paper deals with the seasonal aspects on Ailanthus excelsa Roxb. Study of protein estimation showed that maximum amount was observed during monsoon season (23.44±0.53); however minimum was recorded during summer season (5.97 ± 0.09). Maximum amount of chlorophyll were observed during winter season (10.89 ± 0.05 mg/g.fr.wt; 3.93 ± 0.02mg/g.fr.wt); however minimum during summer season (4.09 ± 0.05 mg/g.fr.wt; 2.98 ± 0.04 mg/g.fr.wt). Amino acids showed highest amount during monsoon (2.03 ± 0.13) and lowest during summer (1.31 ± 0.04). Present study showed that the best time for collecting plants for medicinal uses is monsoon. and winter.