Abstract: The alien leafbeetle Ophraella communa Lesage has spread to eastern provinces including Jiangsu, Zhejiang, Anhui, Jiangxi, and central southern provinces including Hunan and Hubei. Its main host plants are the invasive ragweed, Ambrosia artemisiifolia Linn., and occasionally Xanthium sibiricum Patrin., a plant species most close to the ragweed. It took 29.8, 26.07, and 22.2 d to complete a generation at constant temperatures of 24, 27 and 30℃, respectively; but 21-29 d in the field at Nanjing city. Among the four generations observed in outdoor cages, the first three from June to August were similar in development duration, survivalship, and fecundity; but for the forth generation, development was much slow, survival rate, obviously low, and fecundity (108.8 eggs per female), less than half of previous generations. Development threshold temperature was 11.5℃ and effective accumulated temperature for a generation was 373.5 degree-days. It is estimated that five generations can occur per year in Nanjing city.