Passenger train side wall structure and assembling method thereof

The invention discloses a passenger train side wall structure and an assembling method thereof. Framework modularization design is conducted on the side wall structure by taking windows as the unit. The side wall structure comprises a door frame, a door frame wall plate, at least 2 unit framework modules and a side wall plate. Each unit framework module is a rectangular frame structure formed by mutually-perpendicularly welding stand columns and short longitudinal beams around the windows. Whole framework modules are welded through the short longitudinal beams between the door frame and the unit framework modules as well as between the two unit framework modules. The stand columns and the short longitudinal beams adopt a B-type section structure. The side wall plate is welded and fixed to the unit framework modules. The door frame wall plate is welded to the periphery of the door frame. The thickness of the door frame wall plate is higher than the thickness of the side wall plate. Compared with the prior art,