Soil-atmosphere exchanges of CO_2,CH_4 and N_2 O along a slope (lower,middle and upper slope positions) of natural secondary Pinus tablaeformis forest in Huoditang Area on the southern slope of Qinling Mountains were monitored over a whole year. The fluxes of those greenhouse gases were measured using static chamber and gas chromatography techniques. The differences in the amounts and patterns of CO_2 and N_2O were attributed to the variations in soil texture and water filled pore space (WFPS) along the slope positions. Soil texture of the lower slope position was loam,so soil organisms could subsist in surface soil due to its suitable moisture conditions. The mean values of soil CO_2 fluxes and CH_4 fluxes at the lower slope position were (156.499.72) mg·m~(-2)·h~(-1) and (77.4314.27) mug·m~(-2)·h~(-1),respectively. Those two fluxes values of the lower slope position were higher than those of the other two slope positions. Soil texture of the middle slope position was silt loam with the minimum soil particle diameter,which led to the mean values of soil CO_2 fluxes and CH_4 fluxes being lower than the other two slope positions. Among slope positions,the avergage N_2O emission rate was the highest in the middle slope position with the value of (9.570.66) mug·m~(-2)·h~(-1) . Soil N_2O fluxes of the middle slope was significantly higher than that of upper slope (p<0.01) . In the upper slope position,soil texture was sandy loam,which led to the largest soil porosity and the lowest vegetation coverage among the three slope positions. The mean values of N_2O emission at the upper slope position was merely (5.590.74) mug·m~(-2)·h~(-1) and was lower than the other two slope positions. In general,Pinus tablaeformis forest soil acted as sources for CO_2 and N_2O,but served as sink for CH_4 . The CO_2 emissions demonstrated clear seasonal pattern and was significantly positively correlated with soil temperature (p< 0.01) . In comparison,N_2 O emissions mainly occurred in non-growing season due to the effects of freezing and thawing. At the end of the growing season,there was a consumption peak of N_2O at the middle slope position,which may be due to rainfall event. During the growing season,the presence of CH_4 consumption peak occurred concurrently with rainfall events both in lower and upper slope positions. However,occasional periodic of CH_4 emissions at the middle slope position was also observed during non-growing season,which might due to the high soil moisture content. The values of global warming potential at different slope positions were the highest at the upper slope position,the lowest at the middle slope position,and intermediate at the lower slope position.