The invention discloses a construction method for simultaneously pouring metro rail top air passages and a middle plate, and belongs to the field of tunneling. Construction of a middle plate lower side wall of a station is firstly carried out, and concrete pouring and form removal are completed; and then construction of the rail top air passages and the middle plate is carried out. The rail top air passages and the middle plate are constructed according to the following steps that a, construction of the rail top air passages, a middle plate support except the corresponding position of the railtop air passages, base plate templates and external templates of rail top air passage vertical walls is carried out; b, reinforcing bars of the middle plate base plates except the corresponding position of the rail top air passages, the rail top air passage vertical walls and the rail top air passage base plates are manufactured and installed; c, construction of interior templates of the rail topair passage vertical walls, the base plate templates and middle plate supports of the rail top air passage positions is carried out; d, construction of reinforcing bars of the middle plate is carriedout; e, concrete pouring of the rail top air passages and the middle plate is carried out; and f, form removal is carried out. According to the construction method for simultaneously pouring the metro rail top air passages and the middle plate, the quality of concrete pouring of the rail top air passage vertical wall is ensured, and integrality of concrete bonding of the rail top air passage vertical wall and the middle plate is enhanced.