The coalition in interrelated conflicts with hierarchical structures is analyzed within the framework of basic hierarchical graph model as an extension of graph model for conflict resolution. A basic hierarchical graph model consists of two local graph models with three decision makers: one common decision maker supervising both local graph models, and two local decision makers, each of whom takes part in one local graph model. Two types of coalition, between the common and one local decision maker, and between two local decision makers are discussed. Theorems are proposed, indicating that transition from one equilibrium to another, called equilibrium jump, can only take place in the coalition consisting of common and local decision maker. The change to a more preferred equilibrium for local decision makers could only take place when they temporarily sacrifice their interests. An illustrative example of hierarchical disputes over achieving emission goals between the national and two provincial governments in China are investigated. The results suggest that agreements between the national and one provincial government can be reached. The province will achieve stricter emission goals when being subsidized by the national government. Agreements between the two provinces cannot be formed without the participation of the national government. This study can provide courses of action for decision makers under coalition in dealing with hierarchical conflicts.