A new hydroforming process for manufacturing corrosion-resistant-alloy (CRA)-lined pipe is proposed to overcome the disadvantages in existing technologies, and a new kind of hydraulic expansion device for bimetallic CRA-lined pipe has been researched and developed. Its operational principal and technical characteristic is also introduced. The stress and strain in the liner and outer pipe during the hydroforming process have been analyzed and the mechanism of hydraulic expansion method is studied theoretically. The final forming pressure formula is suggested and the theoretical analysis is verified by experimental investigation. The results indicate that the new technology is feasible and can be applied in industrial production.