Lysimachia laxa is a perennial herb belonging to the family Primulaceae and Gymnocladus assamicus is a critically endangered species of the family Caesalpinioideae contain biologically active substances. The present investigation deals with the evaluation of antioxidant activity of the different parts of these two plants and to determine the best solvent for extracting the antioxidant components. In our research three different solvents (acetone, methanol and aq. methanol ) extracts from different parts of these two plants were used to examine the effects of extraction solvent on total phenolics, flavonoid, flavonol content, reducing power and 1,1-Diphenyl-2- picrylhydrazyl (DPPH) radical scavanging activity. Results showed that extraction solvent had significant effects on antioxidant activity of these two plants. The highest content of total phenolics, flavonoids and DPPH scavenging activities were found in the aq. methanol extract. The methanol had the highest extraction capacity for the flavonol components from these two plants. The highest reducing power was found in the aq. methanol extract of L. laxa and the same was observed in the methanol extract of G. assamicus. Results also showed that the extraction yields of antioxidant components is depending on the polarity of solvent. With increased in solvent polarity from acetone to aq.methanol, amount of extractive materials increased in both the plants. The overall results showed that the aq. methanol extracts of whole parts of L. laxa and G. assamicus showed potent antioxidant activity.