The invention relates to a suspended-cable steel-concrete composite-structured submerged floating tunnel and a construction method of the suspended-cable steel-concrete composite-structured submerged floating tunnel. The tunnel 
barrel body of the suspended-cable steel-concrete composite-structured submerged floating tunnel is a steel-concrete composite shell, the outer-contour 
diameter of the shell is 10 to 15 meters, a supporting frame is arranged in the tunnel 
barrel body, the supporting frame is formed by connecting longitudinal baffle plates and transverse baffle plates, an auxiliary passage and an air gap are formed between the supporting frame and the shell, a travelling lane is formed by the supporting frame, the travelling lane comprises two lanes, and the tunnel 
barrel-body part is connected with a 
submarine uplift 
pile through an anti-floating 
suspended cable; the steel-concrete composite shell is formed by pouring fine aggregate concrete into a position between an inner-layer steel plate and an outer-layer steel plate through 
spray irrigation; a transmission pipeline is laid in the auxiliary passage, and a passage is also formed by laying a baffle plate on the transmission pipeline; one auxiliary passage on the lateral wall of the tunnel barrel body is an 
emergency evacuation passage, and the auxiliary passage is provided with an evacuation opening; an automatic draining device and a ventilation opening are arranged at the upper part of the tunnel barrel body, and an automatic ventilating device is installed at the ventilation opening. The suspended-cable steel-concrete composite-structured submerged floating tunnel has good stability, the 
structural safety and the travelling steadiness of the tunnel are ensured, the construction method is simple, the tunnel is convenient to manufacture, and the usage amount of tunnel steel can be effectively reduced.