Abstract: Total effective vertical load effecting on pipe top and vertical reactive force on pipe bottom distributes almost uniformly along pipe's horizontal diameter and base bed width while the pressure over horizontal soil on both sides of the pipe distributing in parabolic rule. Based on the fact, analyzes internal force and distortion in buried flexible pipeline under two conditions with and without internal pressure, thus derives a series common calculating formula and enumerates calculating examples on pipe bending moment (or stress) and amount of deflection for buried steel pipeline crossing, of which, some formula can be used directly for structure design of steel pipeline's road and railway crossings, also can be used as direction for the design of other flexible pipeline (such as plastic pipeline).