The effects of soil nitrate concentration on denitrification potential and products’ composition were studied under laboratory culture, using sealed, submerged and anaerobic incubation method. The results showed that denitrification potential increased with the rise of nitrate concentration and a good linear relationship (R2 = 0.94, P<0.01) presented between them in the range of nitrate concentration of 10 to 200 mg/kg. The denitrification potentials of the experimented samples ranged from 0.024 to 0.224 mg/(kg×h). N2O was always the dominant product of denitrification, accounting for 56% - 92% of the total denitrification products, and NO was a minor product of denitrification, accounting for 6% - 40%. Soil reduction condition of in-situ field should be not as strong as laboratory incubation. Therefore, the main end product of subtropical acid forest soils of China is not N2 but N2O and NO. This conclusion may explain the reason why this soil has a large N2O emission regardless of its low denitrification rate.