Soil respiration, as an important ecological process of material cycle and energy flow in forest ecosystem, is one of the main fluxes in the global carbon cycle, and plays an important role in the global carbon cycle and carbon balance. There are many factors that affect forest soil respiration, mainly non-biological factors such as soil temperature, water content and air temperature, etc. However, with different climatic zones and forest types, forest age has an important impact on carbon storage and carbon distribution in forest ecosystems, and there is also great uncertainty of the impact on soil respiration. In this paper, soil carbon flux system LI-8100 was used to measure soil respiration and its components in Castanopsis eyrei forests (18 a, 36 a, 54 a, and 72 a) of different forest ages in Wuyishan Nature Reserve. Meanwhile, soil temperature of 5 cm depth and soil water content were simultaneously measured. The results showed that: (1) the seasonal dynamics of soil respiration in Castanopsis eyrei forests with different forest ages presented a single peak trend, and the effect of forest age on soil respiration in winter was not significant (P>0.05). The soil respiration in 18 a Castanopsis eyrei forests in autumn was significantly different from that of the other three forest ages (P<0.05), and the forest age had no significant effect on the seasonal changes of soil water content (P>0.05). (2) Fitting R² of soil temperature of 5 cm depth and soil respiration in different forest age Castanopsis eyrei forest was significantly higher than fitting R² of soil water content with soil respiration. With the increase of forest age, the Q₁₀ value of soil respiration temperature sensitivity index showed an upward trend, which was 1.551, 1.589, 1.640 and 1.664 in turn, while the Q₁₀ value of soil respiration temperature sensitivity index of 54 a and 72 a Castanopsis eyrei forest was significantly higher than that of 18 a and 36 a Castanopsis eyrei forest (P<0.05). (3) Soil water content and soil temperature of 5 cm depth together explain 86%-90.3% of soil respiration variation. The root biomass of 0-60 cm soil layer and soil temperature of 5 cm depth jointly explain 88.3%-91.8% of soil respiration variation. Thus it can be seen that the two-factor fitting of biological factor and abiotic factor can better explain the soil respiration variation of different forest ages. When studying the soil respiration and carbon sink function of forest vegetation in the future, the determination of biological factors should be strengthened on the basis of considering the difference of forest age and season.