The sweetpotato whitefly (Bemisia tabaci biotype “B”) is able to disperse among various host-plants. This whitefly′s dispersal activity among three host species, including cucumber, cotton and water spinach, was investigated in the laboratory, where one of these host species with whiteflies was served as a source host while all the three host species without whiteflies were used as trap hosts. The number of adult whiteflies dispersed to different trap hosts was positively correlated to the host preference levels and negatively correlated to the distance between the two hosts. The number of adults moved to a new host was positively correlated to the population density on the source host. The ratio of adults dispersed from less preferred hosts was higher than that from preferred hosts when the population density on the source host was relatively high. The number of adults dispersed was negatively correlated to host nutrition levels. Whitefly migration in an ecosystem was discussed.