Building environment and energy application engineering city gas engineering direction pipeline network planning graduation design is limited by hydraulic calculation means, and there are problems such as unreasonable pipeline network scheme, low-efficiency hydraulic calculation, and incomprehensive working condition analysis, etc. The introduction of virtual simulation software as a new teaching method can significantly improve this situation. This paper analyzes the influence of hydraulic calculation methods on the design of pipeline network planning, and introduces the virtual simulation software suitable for graduation design. The changes of planning schemes, hydraulic calculation ability, analysis ability of accident conditions, and emergence and completion of new problems after using virtual simulation software as auxiliary design method in graduation design are compared and analyzed. Conclusion that virtual simulation software can significantly improve the quality of graduation design is obtained.