Abstract: Wave motion method is used to calculate the seismic response of bridges in seasonal frozen or permafrost regions. The effect of frozen soil layer on the seismic response of bridges is studied. The seismic force distribution on bridge piers is obtained for various conditions of frozen soil thickness and height of bridge piers. The calculation results indicate that the frozen soil layer has remarkable effect on the seismic response of bridges. The influential law of frozen soils on the bridge pier with different kinds of foundations is similar. The effect of frozen soils on the seismic response of bridge piers is prominent with the height of the bridge pier ranging from 10 to 22 meters. The seismic response of bridge piers in winter and summer seasons has remarkable distinction. The seasonal effect should be considered in the seismic design of bridges.