Abstract: A new exotic species of Asteraceae (Compositae) has been appearing in Tianjin City and Hengshui and Langfang of Hebei Province. The result of our investigation shows that it is Flaveria bedentis (Asteraceae), which has never been reported in China before. According to literature references and its ecology, we assign a Chinese name to it, and introduce its original and expanded distributions in the world, as well as the characteristics of its morphology, physiology and ecology. An assessment of its primary invasiveness indicates that F. bidentis is a highly dangerous exotic annual weed with very strong invasiveness, especially to ecosystems of croplands and grasslands. We put forward strategies for preventing and controlling this weed in order to eradicate it as early as possible. We appeal to experts and government departments to make efforts to investigate its route of invasion, to analyze the potential regions it could invade and occupy, and to assess its invasiveness and study strategies to control its diffusion.