Abstract: As a new kind of technology,the virtual reality is more and more recognized by geographical industries in recent years.In this paper,several key points on the application of virtual reality to valley simulation are discussed based on the construction of Dujiangyan virtual-reality system,including multilevel terrain construction,fluid simulation,scene roaming controlling,multi-subject switching,project simulation and database connection,the research of all these aspects would be significant to the virtual reality application to valley simulation.