Taking the virtual simulation experiment of ventilation system balance adjusting as an example, the application of virtual simulation experiment to undergraduate experimental teaching in building environment and energy application engineering is explored. The implementation results show that although virtual simulation experiment can make up for the deficiencies in conventional experimental equipment, such as insufficient experiment instruments, experiment venues, teaching expenses, etc., and can enrich the experimental resources, it is low-cost, high efficiency, and strong scalability. There are still certain problems of this kind of experiment. Practical teaching and traditional experiment for undergraduates should be considered for virtual simulation experimental platform developing, experiment content setting, process implementation and grade evaluation. Virtual experiments and conventional experiments should complement each other, so as to achieve the purpose of improving the experimental teaching level and teaching effect.