A new large-span timber footbridge located in Dali city was designed by three-span timber arch structure system connected by traditional mortise ten on joints. In order to prove the structural safety and comfortability of the arch bridge，the modal analysis and static analysis of the structure were conducted by using a finite element software SAP2000，the stability of main loaded members under the most unfavorable combined loading condition was checked. The analysis results show that the pedestrian bridge has good comfort under seismic load and wind load and avoids the fundamental frequency range of pedestrian load harmonic，such that the obvious phenomenon of syntony induced by walk hardly occurs. The wind load is not the main factor controlling the structure safety. The overall stress of the supported arch bridge is in a safe state，the maximum stress occurs near the arch foot. Under the worst combined loading condition，the main loaded components meet the safe requirements. The design of this project can provide a reference for similar engineering.