铁路隧道工程项目往往地处深山，地势起伏大，植被茂密，地形复杂，使得测量工作难度增大。对于长大隧道，GPS测量方法成为首选方案，然而由于地形条件限制，GPS控制点的选择与控制网的布设很难满足相应规范要求。以新建东北东部铁路荒沟隧道GPS控制测量为实例，重点介绍在困难地理环境中铁路长大隧道的GPS控制网建立、观测方案确定、过程实施与后期数据处理、成果检验分析及成果应用一完整过程，最终保证隧道高精度贯通，可为以后的类似工程提供参考。

Railway tunnels are always located in mountains. As a result of uneven topography, dense vegetations and complex terrain, it is difficult to carry out the survey works. For long tunnels, GPS survey is the favorite method. Due to the limit of the topography and terrain conditions, however, the selection of the GPS control points and the arrangement of the control network can not meet the requirements of the corresponding specifications. Based on the application of GPS control survey in Huanggou tunnel on DalianMudanjiang railway in Northeast China, the author presents the complete GPS survey process for long tunnels in complex geographical conditions, including GPS control network establishment, survey scheme determination, survey execution, survey data processing, survey result verification and analysis and survey result application. The above technologies guarantee the highaccuracy breakthrough of the tunnel. The paper can provide reference for similar projects in the future.