The invention relates to a manufacturing method of a space curve profile steel component. The manufacturing method comprises the following steps: (1) part manufacturing: three-dimensional analysis software is adopted to loft a curve structure to obtain an unfolding shape of a space curve plate; a process quantity is added; and a part is produced through high-precision numerical control flame cutting equipment; (2) curved surface forming requirement: the minimum curvature in the plate length direction is calculated by analyzing the space curve plate; roller plate equipment is used for prebending; and a characteristic point reaches a designed linetype requirement by a numerical control ejection mode; (3) plate unit production requirement: a special jig model is clamped; reinforcing ribs are assembled in sequence; the assembly gaps and angles of the reinforcing ribs are controlled; and a process with low line energy can be adopted to weld during welding; and (4) steel component production requirement: a special jig model is produced according to the characteristic point; the tightness between a baseplate of the steel component and the jig model is guaranteed; separation plates and other plates are assembled in sequence; and the tightness of all the plates is guaranteed to realize whole linetype of the structure.