Abstract:Accurate estimation of ecosystem respiration (Reco) in forest ecosystems is critical for validating terrestrial carbon models. Continuous eddy covariance measurements of Reco were conducted in a coniferous and broad-leaved mixed forest located in Dinghushan Nature Reserve of south China. Reco was estimated and the controlling environmental factors were analyzed based on two years data from 2003 to 2004. Major results included that: (1) Reco was affected by soil temperature, soil moisture, canopy air temperature and humidity, where soil temperature at 5cm depth was the dominant factor. (2)Exponential equations such as Van′t Hoff, Arrhenius and Lyold-Talor can be used to describe the relationship between Reco and temperatures with similar statistical significance, while Lyold-Talor equation is the most sensitive for temperature index(Q10)；(3) The multiplicative model driven by soil temperature (Ts) and soil moisture (Ms) was more corresponsive to Reco, it explains more Reco variations than Lyold-Talor equation, both for higher and lower Ms. however, there was no statistical difference between the two models. (4) Annual accumulated Reco of the mixed forest in 2003 was estimated as 1100-1135.6 gCm-2a-1 using daytime data, which was 12%-25% higher than Reco (921-975 gCm-2a-1) estimated by nighttime data. The results suggested that using daytime data to estimate Reco can avoid the common underestimation problem of eddy covariance methods. The study provides method basement for further study of accurate estimation of NEE in the coniferous and broad-leaved mixed forest in southern China