The invention relates to a manufacturing method of a cold drawn welded pipe for a precision oil cylinder. The manufacturing method comprises the following steps: longitudinal shearing, rolling forming, high-frequency welding, tensioning, online eddy current inspection, stress relief annealing, normalizing air cooling treatment, pre-straightening treatment, pipe cutting, pinching, acid washing treatment, phosphating treatment, saponification treatment, cold drawing, induction furnace quenching treatment, tempering treatment in a box type furnace, straightening treatment, honing, magnetic leakage inspection and pipe cutting measurement. A product obtained by the method has the advantages of high yield strength, high tensile strength, precise size, smooth surface, high processing and forming speed, high yield, obviously improved manufacturing precision, good surface smoothness of the cold drawn welded pipe, low roughness, reduced subsequent gold processing, improved utilization rate of steel, reduced manufacturing cost and capability of promoting energy conservation and environmental protection.