Ash is the inevitable residues on the soil surface in burned area. Mineral and organic matter of ash can be released into the soil ecosystem through precipitation and surface runoff, which is an important way for fire to indirectly affect the restoration process of the post-fire ecosystem during a certain period of time. However, the ash from the same fuels but produced by different fire behaviors may have different ecological functions. In order to understand the influence of fire behavior on ash and their potential effects on the nutrient cycle and energy flow in the process of ecological restoration of the burned areas, the influence of fire behavior on the ash stoichiometric characteristics of water-soluble carbon and nitrogen was explored. In this study, the surface fuel of Pinus koraiensis plantation was used as experimental materials, different slopes and fuel moisture content were set as the driving factors of fire behavior, and the indoor simulation combustion experiments of the upslope and downslope forest surface fire were performed on the combustion bed. The influence of fire environment on the stoichiometric characteristics of ash water-soluble carbon and nitrogen and fire behavior indicators was explored by the independent-samples t-test, One-way ANOVA, Multivariate ANOVA, while the distance-based Redundancy analysis was used to explore the relationship of fire behavior and the stoichiometric characteristics of ash water-soluble carbon and nitrogen. The water-soluble carbon and nitrogen content of ash in the upslope fire experiment group was significantly higher than that in the downslope fire experiment group (P<0.01); In the 5° experiment group, the water-soluble carbon and nitrogen content of the ash was increase with fuel moisture content (P<0.05). Further data analysis found that the fire behavior was closely related to the stoichiometric characteristics of the ash water-soluble carbon and nitrogen. The flame width was the most significant factor affecting the stoichiometric characteristics of ash water-soluble carbon and nitrogen, and the correlation coefficients with water-soluble carbon, nitrogen and the water-soluble carbon-nitrogen ratio of ash were:-0.515, -0.317, and -0.550 (P<0.05). The flame height and combustion efficiency were negatively correlated with the water-soluble carbon and nitrogen content of ash, the fire intensity was negatively correlated with the water-soluble carbon-nitrogen ratio of ash, and the duration was positively correlated with the ash water-soluble carbon and nitrogen content (P<0.01). The stoichiometric characteristics of ash water-soluble carbon and nitrogen from the Pinus koraiensis plantation were directly affected by fire behavior and indirectly affected by fire environment. Fire disturbance can have a continuously potential impact on the ecological restoration process of burned areas by affecting the characteristics of ash.