It is very difficult to construct large span steel pipe concrete arch railway bridge due to its complicated structure, no mature similar experience to follow and no relative regulation to be guided by. But it is possible to well construct these types of bridges through finding out their characteristics and key procedures, and adopting completed plant and equipment,proper construction technology and sequences and testing methods as follows: (1) Fully play the advantages of manufacture technical force and advanced equipment to ensure the accuracy of steel members and welding quality. Arrange the complicated procedures to be done in factory,so as to simplify assembling and welding works at site, thus improve the arched accuracy and welding quality. (2) Control the site welding deformation. It is mainly accomplished by adopting the proper technology and construction sequences together with firm supports and necessary site facilities.(3) Welding quality is mainly ensured through adopting proper welding technology and qualified welder with post certificate.