Comparison is made among 4 construction schedules, including adding advance safe tunnel to support main tunnel, adding inclined/vertical shaft, adding branch tunnel and improving the construction speed, by taking Qamchiq extralong railway tunnel in Uzbekistan for example. The construction schedule of adding branch tunnel is adopted and technically and economically analyzed. The construction parameters are determined. Finally, it illustrates that by adding branch tunnel, the construction cost can be reduced and the construction schedule can be shortened.