As a successful self-made important machine, Shanghai’s 120MN forging hydraulic press has become a prominent landmark for the development of China’s industry, which has turned from copying to self-designing and self-manufacturing. Through technical analysis of the design and manufacturing of the body of the machine, especially its columns, beams and cylinders, this paper discusses technical difficulties, lines and measures in the process of the engineering led by Mr. Shen Hong. The case study indicates that the synthetic approach, which combines imitation with model, experiment and technical integration, was effective for manufacturing some major technical equipment independently in China.