Linear elastic constitutive model was used to analyze the stress distribution in the vertical wellbore: Mohr-Coulomb criterion, Drucker-Prager criterion and Mogi-Coulomb strength criterion were respectively applied to calculate the minimum fluid column pressure required to maintain stable wellbore for the crustal stress measurement and monitoring borehole in Pinggu. By the contractive analysis, because of the intermediate principal stress, the minimum fluid column pressure required to maintain wellbore stable could be reduced.