The invention relates to a method for manufacturing a stator bar of an air-cooling 200MW steam turbogenerator. In the manufacturing process, technological innovation is carried out on the aspects of matching between a main insulated dry mica tape and impregnating resin, processes of impregnation, curing and the like of the bar, an anticorona treatment process and the like, so that the insulation thickness of the stator bar manufactured by adopting the process under a rated voltage of 18kV is reduced to 3.3mm, a difference delta tg delta of tg delta under the normal Un and tg delta under a Un of 0.2 is less than 1 percent, a breakdown voltage reaches 6 times of the rated voltage, a working field strength reaches 3.149kV/mm, and no corona phenomenon is generated in the AC (alternate current) withstand voltage test process of the single bar under the condition of 56kV per minute. Due to the adoption of the method, the domestic blank is filled.