Taking the construction geology technology practice of karst tunnels on Yichang-Wuanzhou Railway as an example, construction geology, which is a continuation of engineering geological exploration in construction stage, can be used to solve the problems which do not exist or cannot be solved in exploration stage. Taking advanced geology predication as its subject, aiming at avoiding large-scale construction geological harzards, construction geology refers to the comprehensive engineering geology work for ensuring construction progress, construction safety, engineering benefit and project quality, such as predicting possible displacement of tunnel surrounding rock; forecasting potential salt cavities, faults and underground rivers; finding out potential hydrogeology problems and concealed geological disasters after project completion, etc. Construction geology includes comprehensive advanced geology predication, hydrogeological observation and concealed karst exploration.