The construction of the excavation and support of the subsea tunnel is very difficult, and safety risk is also very high. Relying on the construction of a fault and crush zone of the second subsea tunnel inland, using the method of geologic survey, TSP, flank holes, and analyzing the data, predicting basis geology condition within 45 meters ahead of working face. Combining long term geology prediction with short term geology prediction, comprehensive pre geology prediction is reported. According to its geological property, adopting full sectional grouting upper section in the fault and crush zone in order to strengthen stratum, bench excavation method, and strong support. At the same time, monitoring and measuring convergence, subsidence of crown, and pressure of surrounding rock, by processing of data, and to the construction, is called the information construction of the subsea tunnel in a fault and crush zone. The method is applied to the construction, produces a satisfactory effect.