The invention discloses an extended UML2 sequence chart-based interrupt-drive system modeling method. The method comprises the following steps of 1: extending a UML2 sequence chart and newly adding an interrupt interaction system type for describing interrupt occurrence and response processing; 2: dividing an executive process of an interrupt-drive system into an interrupt external interaction and a plurality of interrupt internal interactions; 3: modeling an interrupt external process according to the specifications of the UML2 sequence chart; 4: modeling the interrupt occurrence and the response processing according to interrupt combination fragments defined in the step 1; and 5: modeling a time constraint of the interrupt-drive system. According to the method, the UML2 sequence chart is extended, so that the interrupt-drive system can be described and a visual and intuitionistic modeling method easy to understand is provided for interrupt-drive system design personnel; and modeling design of the interrupt-drive system, and related model verification, model conversion and model-to-code generation are facilitated.