Abstract: Overhead crossing pipe bridge is a very important structure for long-distance oil/gas pipeline, its reasonable structure design and safe reliability will tatally ensure this kind of pipeline to safe operation. Taking an arch-shape Combined-Arched Pipe Bridge (CAPB) as a research target, the paper applies the first-order second-moment theory to carry out reliability analysis on CAPB and provides the analysis ideas of reliability of CAPB. It considers that the major factors influencing the resistivity of structure members are such random variables as the material performances, geometric parameters and accuracy of models, and put forward the method which determines the target reliability indices β₀, and quantitatively analyses and calculates the structure reliability indices of CAPB with centre-point method. It developes reliability analysis software-CPMRA with FORTRAN language in order to deal with the complicated β equations. The indices results calculated by the software show that the analysis method described in the paper are correct with a high accuracy, and prove that the old design method of CAPB is too conservative to be reasonable in economy.