It is helpful to improve the seismic design theory of long- span continuous bridges for studying the seismic performance of each cantilever construction state． Taking the Bridge 1 in the north of Changbai- Moun- tain international tourism resort as an example，the authors studied it in shutdown phase and the cantilever con- struction process，established the simulation model by using Midas/civil，and analyzed time- history of each construction stage for the bridge． The study shows that long- span bridge cantilever construction in northeastern China can be divided into two- year tasks for construction (suspending in winter)． It is needed to think about seismic stability of the cantilever position in shut- down phase of winter． The effect of longitudinal vibration is the most disadvantageous influence to bridge， and its calculation results can provide reference for seismic design of similar bridges in the future．