The invention relates to a construction method for an underground pipeline passing through a railway line. The construction method includes the following five steps including the first step of construction section railway track reinforcement, the second step of transmitting well and receiving well digging and supporting, the third step of laying of a guide rail in a transmitting well and installation of an ejecting device, the fourth step of casing pipe ejection and soil removal and the fifth step of underground pipeline lead-in and construction. According to the underground pipeline construction method, a casing pipe is installed in a hydraulic ejection manner first, then the underground pipeline penetrates the casing pipe, and the construction process and the railway transportation do not interfere with each other; before construction, a railway foundation is reinforced, the influences of railway foundation spalling during construction on bearing of railway tracks are avoided, and the railway tracks and the railway foundation cannot be damaged; and during construction, the railway tracks do not need to be detached or recovered, the construction period is not influenced by the railway transportation, and the construction cost is greatly reduced.