In order to study the dynamic performance and vehicle-bridge vibration responses of the curved-string truss bridge in service，the vehicle-bridge coupled vibration analysis of the curved-string truss bridge in service are carried out based on the vehiclebridge coupled vibration analysis method which can consider the period of vehicle jumping. The Rainbow Bridge with span of 122 m is taken as an example，the finite element model of the bridge is set up to analyze the dynamic characteristics of the bridge and the dynamic responses of the bridge are calculated while space motorcades cross the bridge，and then，the influences of factors such as speed，number of vehicles，motorcade distribution and road surface roughness on the dynamic responses of the curved-string truss bridge in service are discussed. The result shows that the vertical stiffness of the bridge deck is relatively weak，and the local vibration of the bridge deck is easy to be excited；the vertical vibration and the dynamic responses of the bridge deck increase significantly with the number of vehicles and the number of loaded lanes；the impact coefficient of mid-span displacement of the bottom chords exceed the value of design standard，and the bridge deck vibrates always with a greater degree；the middle and rear wheels of the vehicles are prone to jump，the higher the grade of road surface roughness is，the more jumps of vehicles will occur，and the vehicles are also prone to jump when the road surface roughness is in good conditions.