The causes of lining cracking, waterleakage and ballast bed freezing at portal section of a railway tunnel in Northeast China are analyzed by comprehensive analysis method; and then relevant countermeasures are proposed. The analytical results show that: 1) The cracking of surrounding rock lining is mainly caused by frostheave force of surrounding rock; and it can be effectively avoided by using insulation measure of spraying insulation layer + fireproof mortar and structural reinforcement measure of anchor bolt + crack filling. 2）The water caused ballast bed freezing in tunnel is mainly derived from snow on portal cutting of tunnel and the local waterleakage of inverted arch; and it can be effectively avoided by setting electric heating facilities in ditches on both sides of the tunnel, setting a small dam and horizontal electric heating facilities under the bottom of ballast bed, and setting snowcovered facilities on portal cutting of tunnel and zerofill section of embankment.