The variability of nutrient stoichiometric characteristics of wild apple trees (Malus sieversii) at different altitudes was investigated. Investigation and sampling were conducted at four altitude gradients of 1300 m, 1400 m, 1500 m, and 1600 m in a valley study area over three consecutive years (2016-2018) to analyze the comparative spatio-temporal variation characteristics of N, P, and K stoichiometry in one-year-old branches of M. sieversii and their relationship with environmental variables. The findings revealed that the branch stoichiometric indexes of wild apple trees tended to exhibit moderate and weak variations at different altitudes and in different years; P exhibited the weakest variability and N:K exhibited the strongest variability. The year significantly impacted the five stoichiometric indexes, with the exception of P:K, whereas altitude had a significant impact only on N:P. The twig N, N:P, and N:K was also affected by the interaction of year and altitude. There were no significant differences between branch P (except for in 2017), K, and P:K at different altitudes, although they all displayed significant interannual changes. The branch N, N:P, and N:K all represented significant temporal and spatial variability; however, the changing trends differed. Both correlation analysis and NMDS analysis demonstrated that they own growth status of wild apple trees (dead branch rate, projective coverage, degree of disease and insect pests, and fruit amount), annual precipitation, and soil factors all affected branch stoichiometric characteristics to a certain extent; however, different stoichiometric indices exhibited different responses. In general, the better the plant growth status of wild apple trees, the lower the nutrient contents in one-year-old branches. Consequently, the branch stoichiometric characteristics of wild apple trees exhibit obvious variability at different altitude gradients and temporal scales, and the influencing factors are quite complex.