Abstract: The gas pipeline crossing rivers is under the pressure of different ambient medium, thus bending deformation is easy to occur, which becomes an important hidden hazard to the safe operation of pipelines. Herein, through the stress analysis for the river crossing section of gas pipeline under different ambient medium, a physical model of statics analysis for the floating pipe section was established, and the stress distribution was simulated with ANSYS software to obtain the stress and strain distribution of pipelines. In addition, the influence of the internal pressure of pipelines and the flow rate on the maximum stress of pipelines with different diameters, as well as its rules of change, was discussed. The results show that, with the increase of the internal pressure or flow rate, the maximum stress applied to the pipeline increases, and the growth rate of the maximum stress applied to the pipeline also becomes faster. In the case that the flow rate or the internal pressure is constant, the maximum stress applied to the pipeline increases with the increase of the outer diameter of the pipelines.