Abstract: As the hydrotest for huge fall pipeline in mountain area is impacted by static pressure difference, with multiple pipe sections and greatnumber of field pipe joints, which will not only impact the hydrotest efficiency, but also cause leakage risks of pipeline. Taking the Lanzhou-Chengdu Crude Oil Pipeline as an example, this paper carries out the optimization in hydrotest scheme for huge fall pipeline in some aspects,including calculation of hoop stress, determination of low point stress level, integral tunnel groups hydrotest, and local wall thickness adjustment and so on. After the optimization, the numbers of pipe sections to be tested in Kangxian Pipeline Section are reduced from 45 to 24, and the working efficiency is improved greatly, and reduces the numbers of "Tie-in". The technical points in steel pipe ordering and hydrotest for the pipe section crossing highways and rivers are analyzed, as well as the impact of tested "tie-in" of pipe sections and residual air.