Abstract: Litter decomposition is of great significance for material circulation and energy flow in the ecosystem. In reccent years, due to human factors, excessive nitrogen has entered terrestrial ecosystems, which has changed litter decomposition and nutrient dynamics. In this paper, the leaf litter of Magnolia officinalis were selected as the research object, and six nitrogen deposition levels were carried out by litter decomposition bag method. After 120 days of natural decomposition, the quality of litter and the contents of various nutrient elements were determined, and the effects of simulated nitrogen deposition on the leaf litter decomposition of Magnolia officinalis and nutient release during the decomposition process were explored. The results showed that: 1) With the continuous decomposition process, the mass loss rate of Magnolia officinalis leaf litter showed an overall upward trend, and nitrogen deposition promoted the decomposition of Magnolia officinalis leaf litter; 2) C element showed the release pattern, and the effect of nitrogen deposition treatment on C content was not significant; 3) N element showed the enrichment pattern, and the effect of nitrogen application treatment on N content was not significant; 4) The overall trend of P content was firstly increasing and then decreasing, showing an enrichment and release pattern, and nitrogen deposition had a promoting effect on P content; 5) During the whole simulated nitrogen deposition period, the variation trend of K content fluctuated, but in general, it showed the release pattern, and nitrogen deposition promoted K content; 6) The overall Ca content showed a downward trend, showing a release pattern, and nitrogen deposition promoted the Ca content. The results indicated that simulated nitrogen deposition for 120 days promoted the decomposition of Magnolia officinalis leaf litter, and promoted or had no significant effect on the release of nutrient elements, which provided a theoretical basis for the management of Magnolia officinalis.