Research conclusions: The principles of engineering design and construction of railway in permafrost area should suitable for various geologic characteristics of permafrost. The scientific analysis should be made and concrete treatment measures should be taken in order to guarantee economic rationality, safety and reliability of construction of Qinghai-Tibet Railway. Also the rational preventive measures should be taken for subgrade, culvert and bridge during the period of service in order to guarantee the quality and normal traffic of Qinghai-Tibet Railway, and fundamentally restrain the occurrence and development of water disasters, such as deformation and crack.