In this paper, the working principle of negative pressure isolation evacuation equipments is analyzed, some classic foldable negative pressure isolation evacuation equipments for infectious disease patients at home and abroad are introduced, structural design of negative pressure isolator for infectious disease patients with multi-cavity gasbag structure are carried out, then human ergonomic evaluation about the micro-environment in the chamber is made. The result shows that this equipment can meet the requirement for transporting infectious disease patients, and provide relatively comfortable micro-environment.