Abstract: Cylas formicarius is an important insect pest during the growing and storage period of the sweet potatoes in Fujian, the damage mainly caused by larva biting of the vines and potato chunks. Since the damage was not obvious and the single control efficiency was not good, the loss ratio could be 20% to 30% and the damage to the sweet potato production in Xiang’an was serious. A research was made to analyze the characteristics of generations and overwintering of Cylas formicarius in Xiang’an area after monitoring the growth and decline of Cylas formicarius in the field by using gyplure, and at the same time to compare the dynamic state differences of damage of different kinds of fields and Cylas formicarius. It showed that in Xiang’an area of Xiamen, the cardinality after wintering of Cylas formicarius in dry land (138.56 /m²) was bigger than that in paddy field (98.56 /m²), and the percentage of female insects was higher than that of male insects among the imagoes after wintering; the ratio of damaged plants in dry land and farming changed field were higher than that in paddy field, with the percentage being 61.67%, 48.33% and 20%; the peak season of damage was from October to November; the damage ratio of the main cultivar ‘Chaoshu 13’ was higher than that of ‘Pei 26’.