Abstract: Aiming at the contradiction between massive data of railway BIM and bandwidth of current network transmission, considering with the data characteristics of railway 3D scene, the article proposed a data realtime compression method for massive data of railway BIM. Three-dimensional coordinates were reduced to twodimensional by localization, and the bits were also significantly reduced by relative treatment. A lossless and high compact data format was defined to store the coordinates for network transmission of railway sense. The inter frame prediction method suitable for railway scene rendering was proposed to reduce data redundancy of adjacent pile numbers. The bit stream was further compressed by using adaptive arithmetic coding and higher compression ratio was obtained.