The line-shape of catwalk of long-span suspension bridge is obtained by using the segmental catenary method to carry out the iterative calculation, where all the bearing cables are considered as one cable, and transversal passages and gantry are treated as nodes which divide the catwalk into several segments. The difference of line-shape and force between catwalk bearing cable and gantry bearing cable is not usually considered, but the line-shape of two kinds of cables is actually inconsistent because of the constraints from gantries. Based on the segmental catenary method, considering the different states of bearing cables （ DSB calculation method）, fine calculation is carried out. This method is applied to the design of a suspension bridge＇ s catwalk, and is compared with the traditional calculation method. It is obtained that the result is more reasonable and accurate by the coordination calculation method considering different states for two kinds of load-bearing cables, which is worth considering in the nrocess of design and optimization for catwalk.