[Objective] The study investigates the effects of different light intensities on the photosynthetic characteristics of the invasive species Bidens frondosa and the native species Lactuca indica，aiming to provide a reference for revealing the invasion mechanism of B. frondosa. [Methods] Potted seedlings of the two plant species were used as the materials. Shading shelters were established using black shade nets with light intensities of 100%，40%，24%，and 14%，and differences in leaf photosynthetic characteristics under varied treatments were compared. [Results] 1） Under 100% and 14% light intensities，B. frondosa exhibited significantly higher maximum net photosynthetic rate（P_max）and light saturation point（LSP），but lower light compensation point （LCP）than L. indica. 2）Under 100% and 14% light intensities，the chlorophyll content of B. frondosa was significantly higher than that of L. indica. 3）Under 100% light intensity，B. frondosa showed significantly higher carboxylation efficiency（CE），maximum carboxylation rate of Rubisco（V_c，max），maximum regeneration rate of RuBP（J_max），and photorespiration rate without CO₂（R_p）than L. indica. V_c，max was also significantly higher under 14% light intensity，while R_p decreased under medium and low light intensities and was lower than L. indica. 4）B. frondosa exhibited greater plasticity in P_max，R_d，CE，A_max，R_p，and J_max than L. indica. [Conclusion] The invasive plant B. frondosa shows higher photosynthetic capacity and greater photosynthetic physiological plasticity under different light intensities，indicating a broader adaptability to light intensities.