Abstract: Jianfengling tropical mountain rainforest (JTMR) in Hainan province is one of the typical tropical forest ecosystems, whose long term climatic dynamics is important to the global change research. Based on the conventional meteorological data of national field observation station in Jianfengling tropical forest ecosystem from 1980 to 2005, the abrupt change and anomaly of climate in JTMR were analyzed by the accumulative anomaly method and Mann-Kendall test. The results show that the annual mean air/ground temperatures, the annual mean maximum and minimum air temperatures, the annual accumulated temperature and the mean vapor pressure change from the low to the high during recent 26 years, and the abrupt change occurs in 1990. The mean annual wind speed changes from strong to weak, and the abrupt change appears in 1993. Air temperature and ground temperature are high abnormally when the strong intensity ENSO event happens in 1998. All of these mentioned above indicate that the climatic change of forest land is just the significant response to the global abnormal climate change.