The fortification of civil air defense section of metro main line under limited space is difficult, the dimension of airtight blast partition door with singleleaf or bigandsmall doubleleaf is overlarge, and the installation is difficult. Hence, a new type of doubleleaf airtight blast partition door for singletube singletrack metro tunnel is developed based on the design principle and applicable experience of traditional airtight partition door. The door with small dimension can reduce the space needed and manufacturing, transportation and installation works. The sealing of catenary, steel rail and middle joint of door can be carried out by adopting catenary sealing device, removable threshold sealing beam, rail sealing box and pressure sealing strip under the condition that the rigid catenary is connected. The practice indicates that this kind of doubleleaf airtight blast partition door is rational in structure, perfect in function, reliable in performance, flexible in opening and closing, which can meet the fortification requirement of metro civil air defense and provide technical support and guarantee for metro civil air defense construction.