Ecophysiological properties, such as photosynthetic characteristics, contribute significantly to the success of many invasive plant species. Using a field photosynthesis measurement system (LI-6400), we determined and compared the photosynthetic characteristics of a common invasive plant in eastern Guangdong Province, China, Lantana camara L. and three species often associated with it, Bidens pilosa L., Urena lobata L. and Achyranthes aspera L., Our results showed that: (1) Light saturation point and light compensation point of L. camara were 1225 μmol·m-2·s-1 and 13.58 μmol·m-2·s-1, respectively, which were significantly lower than those of all three associated species (p< 0.05), AQY of L. camara was equivalent to A. aspera and higher than U. lobat. (2) CO2 saturation point and CO2 compensation point (CCP) of L. camara were also lower than that of A. aspera, but higher than those of the other two species. However, Pmax (20.08 μmol·mol-1) of L. camara at CSP was much higher than A.aspera under study, and CE of L. camara was equivalent to B. pilosa and higher than A. aspera. (3) Increased photosynthetically active radiation and CO2 concentration did not significantly affect either stomatal conductance or transpiration rates, but greatly improved the water use efficiency (WUE) of L. camara. These data indicate that the ecophysiological advantages of L. camara could contribute to its success as an invasive species.