On the basis of site investigation

the main damage types of road drainage canals in permafrost regions of Tibetan Plateau are analyzed.The damage includes relative shifts occurred in the bottom of drainage canals and lateral horizontal cracks.These diseases are mainly caused by repeatedly uneven frost heaving and thawing settlement of the foundation and vertical frost heaving force resulted from freezing of soil at canal′s wall.According to mechanism of these diseases

the design methods of prevention measures should take into account two aspects

namely reducing uneven frost heaving and thawing settlement of the foundation

and weakening horizontal frost heaving force.A new structural drainage system is designed in this paper

and its practical effect is good undergoing two years.Its maintenance period can prolong and maintenance costs can also reduce when the new structure of drainage canal is used for embankment engineering in permafrost regions.