[Background] Bactrocera dorsalis (Handel) is a major pest on fruit crops in tropical and sub-tropical area, including Hainan Province, China. [Method] Pheromone lures for capturing male adult B. dorsalis were used to study the seasonal dynamics in four areas in Danzhou City, Hainan. The correlation between adult numbers and temperature and rainfall was also examined. [Result] B. dorsalis adults emerged throughout the year, with fewer adults in winter and more in the summer. The peak population densities were observed in June, with 327.6 adults captured during the month in a mango orchard, 182.8 in a vegetable field, 150.0 in a built-up area, and 209.6 in a botanical garden. An exponential increase in captures was found with increasing temperature in the mango orchard (correlation coefficient R=0.799), while lower correlation was found with rainfall (R=0.367). [Conclusion and significance] The results could serve as a useful theoretical basis for formulating IPM strategies to B. dorsalis in Danzhou.