It frequently happens that the power transmission lines are parallel to or cross over the buried oil/gas pipelines. This paper analyzed the electrostatic induction, magnetic induction and ground potential of transmission lines and buried oil/gas pipelines; and obtained a computational formula for induced voltage of power lines on oil/gas pipelines. On this basis, the induced voltage of 1 000 kV power transmission lines on the buried oil/gas pipelines was calculated, which provided reference for design of transmission lines cross over buried oil/ gas pipelines.