Soil recalcitrant organic carbon (ROC) is a highly stable component of soil organic carbon. It accounts for a relatively high proportion of the soil organic carbon pool, and the change in its content indicates the dynamics of the soil organic carbon pool. Exogenous nitrogen (N) input is a key factor affecting soil ROC. However, how different types of N components affect ROC is still unclear. Based on this, nitrate N (KNO₃ and NaNO₃), ammonium N (NH₄Cl and (NH₄)₂SO₄), mixed N (NH₄NO₃), and amide N (Urea) were fertilized with equal amounts (N 10.0 g/(m²·a)) to temperate forest soils to investigate the effects of different N fertilizers on temperate forest soil ROC. The results showed that different types of N addition significantly increased soil ROC content and recalcitrant carbon index (RI) by 73.4%-161.9% and 52.3%-137.4%, respectively. Among them, the increase of ROC content after ammonium N treatment was the largest, and the increase of ROC content after NH₄Cl and (NH₄)₂SO₄ treatment was 133.7% and 161.9%, respectively. It was because ammonium N showed the strongest inhibition effect on the activities of lignin peroxidase, laccase, polyphenol oxidase, and the greatest reductuion effect on pH, which decreased by 35.7%-38.7%, 24.9%-25.3%, 38.1%-56.9%, and 10.8%-11.4%, respectively. Amide N showed the weakest inhibition on the activities of these enzymes (declined by 13.8%, 14.6%, and 24.6%, respectively), and the increase in ROC content was correspondingly lower (73.4%). Nitrate N addition declined most the activity of manganese peroxidase, and the decreases of KNO₃ and NaNO₃ treatments were 10.5%, and 24.0%, respectively, which led to an increase of ROC content by 109.6%-111.0%. In conclusion, the impacts of N types should be considered when accurately predicting and evaluating the response of ROC to N deposition.