In the face of global climate change, an accurate grasp of the biogeochemical cycling process and its key influencing factors in terrestrial forest ecosystems is beneficial for maintaining the multifunctionality and the stability of the ecosystem, achieving increased and extended carbon sink services, and continuously enhancing and improving people's well-being. Redundancy analysis (RDA) and Variance partitioning analysis (VPA) were used to clarify the key factors affecting the spatial variation of the stoichiometric characteristics of bulk soil and ectorhizosphere soil of the Picea crassifolia forest from the perspective of soil, forest stand and topography in this study, in order to explore the influencing factors and the ecological response of soil ecostoichiometric characteristics to the altitude of the forest of P. crassifolia, which is the constructive species in the forest ecosystem of Helan Mountains. The results of experiment showed that:(1) the contents of C and N nutrients in bulk soil and ectorhizosphere soil of P. crassifolia forest in Helan Mountains were remained at a high level, while the growth of P. crassifolia in the high-altitude areas was affected by the high P limit of soil. Compared with the bulk soil of P. crassifolia forest, the ectorhizosphere soil has higher capacity of nutrient turnover, such as the decomposition and mineralization of organic matter, and the potential of P retention, although the nutrient content of ectorhizosphere soil was relatively lower. (2) there were significant differences in bulk soil and ectorhizosphere soil ecostoichiometric characteristics of P. crassifolia forest between different altitudes (P<0.05). With the increase of altitude, the bulk soil and ectorhizosphere soil nutrients and ecostoichiometric ratios changed differently, and all soil nutrient contents and ecostoichiometric ratios of bulk soil were significantly different between different altitudes except total nitrogen content (TN) (P<0.05), and total phosphorus (TP) and C/P ratio (C/P) had significant differences of ectorhizosphere soil (P<0.05). (3) three groups of influencing factors, i.e. the soil, forest stand, and topography, together accounted for 61.35% and 39.64% of the variation of the ecostoichiometric characteristics of bulk soil and ectorhizosphere soil, respectively. It was found that altitude, microbial biomass carbon (MBC), and microbial biomass phosphorus (MBP) were the dominant factors affecting the vertical variation of the ecostoichiometric characteristics of bulk soil, while those of ectorhizosphere soil were significantly affected by the normalized difference vegetation index (NDVI). The single effect of soil factors on the ecostoichiometric characteristics of bulk soil and ectorrhizosphere soil was twice and three times as great as that of forest stand factors, respectively. In summary, the spatial heterogeneity of the ecostoichiometric characteristics of bulk soil and ectorhizosphere soil in P. crassifolia forest in Helan Mountains was mainly driven by soil factors, secondly by forest stand factors. The effect of topographic factors was to change vegetation characteristic and soil properties mainly through the redistribution of environmental factors, so as to affect the spatial pattern of soil nutrient stoichiometry in P. crassifolia forest. This study is helpful to evaluate the soil nutrient deficit status and key influencing factors in mountain ecosystems, and is also beneficial for providing a scientific basis and theoretical support for soil nutrient regulation and sustainable management in the forest land from the perspective of ecological stoichiometry.