Based on the data of Xiamen national meteorological station from,1973 to 2021, the variation characteristics of temperature and heat resources were analyzed by climate trend rate, cumulative anomaly method and Mann-Kendall mutation test. The results showed that the annual average temperature in Xiamen rose significantly at an average rate of 0.478 ℃/10 a, and the temperature rise was most obvious in spring. The increase rate of the average maximum temperature (0.515 ℃ /10 a) was significantly higher than that of the average minimum temperature (0.285 ℃ /10 a) . The upward trend of the active accumulated temperature was also observed. The increase rates of annual active accumulated temperature, ≥10 ℃, ≥15 ℃, and ≥20 ℃ accumulated temperatures were 175.57, 246.07, 229.72 and 268.92 ℃ /10 a, respectively. The abrupt change of active accumulated temperature from cold to warm occurred during 1997—2000. Heat resources can effectively improve the yield and quality of thermophilic crops,but may bring about meteorological disasters such as pests and diseases and aggravate the urban heat island effect.