Three main types of Soil respirations(S+L and S) in southern subtropical forests in Dinghushan biosphere reserve were consecutively being monitored over 31 months by the approach of static chamber-gas chromatograph techniques. Research shows that: annual mean contribution rates of litter-fall to soil respiration in the monsoon evergreen broadleaf forest (BF), mixed broadleaf-coniferous forest (MF) and coniferous(pine) forest (PF) reached 27.82%、33.29%和36.35% respectively; Moreover, all three types of forests displayed the same seasonal dynamic features with the peaks contributions of them were from April to September, which accounts for 71.87%、61.89% and 70.39% of annual total contributions of litterfall to soil respiration respectively. Soil respiration(S+L) had an obviously positive relationship with the seasonal changes of litter-fall input（P<0.001; And soil water content had a significant impact on the contribution of litter-fall to soil respiration in the three types of forests (P<0.001); Soil temperature had positive correlativity with soil respiration flux, though it has no distinctive relationship with contribution of litter-fall to soil respiration; the contribution ratios of litter-fall to soil respiration on rainy days were 28.63%、38.20% and 40.12% respectively, which were significantly higher than those in the sunny days in the three types of forests.