Abstract: In view of utilizing Petri net to perform analysis of UML model, this paper proposes a transformation methodology from UML statechart to Petri net in terms of the semantics. Firstly, it gives the formal definition of the UML statechart, uses state sets, transition sets, event sets, guard sets, object sets and refinement functions of the state to describe the features of the UML statechart and designs transfer sets of state concurrency, transfer sets of collision and transfer priorities. Based on the strict formal semantics of the Petri net, the study studies the equivalency between them and proposes a transformation algorithm from UML statechart to Petri net which lays the foundation of automated transformation. Finally, in order to validate the proposed methodology, a novel decentralized railway interlocking system which ensures train safety in stations is modeled and analyzed.