Plants growing in soils with different nitrogen levels under nitrogen deposition, therefore, the study of different provenances of Acer mono play an important role in understanding the response mechanism of nitrogen deposition. In this study, to understand the adaptation and response mechanisms of different provenances of A. mono under nitrogen deposition, nitrogen addition control experiments were conducted on three provenances of A. mono seedlings.The specific leaf area (SLA),leaf dry matter content (LDMC), leaf N content, P content and the N:P response to nitrogen addition in A. mono seedlings were analyzed. The results showed that (1) under different nitrogen addition treatments, the LDMC of A. mono seedlings from Inner Mongolia provenances (NW) and Shanxi provenances (SW) were significantly lower than those of CK, the LDMC of NW and SW increased significantly under the N4 condition. With an increase in nitrogen concentration, the SLA of A. mono seedlings of NW and Beijing provenances (BW) increased significantly under N4;while that of SW increased significantly at the N2 level. (2) With nitrogen addition, only the P_mass of SW increased significantly at the N1 level, and the N_mass showed a significant increase at the N1 and N3 levels. This indicated that under low nitrogen levels, SW can promote the absorption of P, thus, increasing the accumulation of P in plants. At the same time, under low, medium, and high nitrogen conditions, it can promote the absorption of SW to N, which shows that SW can better adapt to the low and high nitrogen environments, and improve its survival ability. (3) Analysis of the variation source and the correlation of each index, under nitrogen addition, revealed that the SLA, LDMC, P_area, and N:P of A. mono were significantly related to nitrogen addition. SLA, LDMC, N_mass, P_mass, N_area, P_area, and N:P showed no correlation between nitrogen addition treatment and provenance interaction; the results showed that the characteristics of A. mono were mainly affected by nitrogen addition. (4) Comprehensive changes of all indicators were shown; under nitrogen addition, the LDMC of NW decreased significantly, and the SLA increased significantly. Furthermore, the N and P contents in the leaves, and the N:P were higher; the LDMC of SW decreased significantly, SLA increased, and leaf N and P content increased significantly. According to the theory of leaf economic spectrum, SW and NW belong to the "quick-investment-income" type, while BW tends to follow the "slow-investment-income" type. Therefore, the different provenances of A. mono show variable responses under condition of nitrogen addition; continuous nitrogen addition affects the internal stability of A. mono.