The invention relates to a structural steel framework of a railway passenger car body. The structural steel framework comprises a base frame welding framework, side wall welding frameworks and a car roof welding framework, wherein a car body framework is formed in a manner that each closed frame body formed by portable assisting beams, vertical beams and a car roof cross beam, and a covering wrapper sheet set are welded together, and has large strength and large rigidity; a bogie of a passenger car is not used, and a scheme of single wheel pairs is used, so that a base frame sleeper beam is replaced with an I-shaped beam, the carrying capacity of the I-shaped beam is better, the I-shaped beam and the base frame welding framework can form a criss-cross beam structure, and the integral stability is good; wheel set seats are large at the upper part and small at the lower part, and are small in size and strong in carrying capacity; a center beam adopts a box type structure, and stiffened plates are arranged in the center beam, so that a closed box type structure is formed for bearing main traction and pulling force; a front end beam and a rear end beam respectively adopt a wing-shaped structure, and the structure is stable; and a longitudinal beam and a cross beam of the car roof welding framework are formed by the welding of deformed steel plates, and the deformed steel plates are high in structural strength, not liable to bend, light in weight, and suitable for the car roof structure.