Taking Xiangrui Street Bridge in Xining as the engineering background, it is a single-arch through continuous beam-arch combination bridge, combining with mechanical analysis and finite element modeling as the main line. The following researches were carried out on the beam-arch cooperation mechanism and structural parameters. According to the expressions of load sharing ratio of arch, bending moment ratio of arch-beam, and deformation ratio of arch-beam, combined with engineering background, the author draws the influence curves of each parameter (suspender-arch ratio of equivalent flexural rigidity, ratio of beam-arch sectional flexural rigidity, rise-span ratio, influence coefficient of axial deformation, side- to main-span ratio, side- to main-span flexural rigidity ratio) and load sharing ratio of arch, bending moment ratio of arch-beam, deformation ratio of arch-beam were drawn. The influence of structural parameters on the load sharing ratio of arch, bending moment ratio of arch-beam, and deformation ratio of arch-beam was also analyzed. It provides a mechanical basis for designers to formulate reasonable structural parameters in the initial stage of scheme design.