Research conclusions: From the f results of field observation and the simulation analysis with finite element method it is concluded in this paper that the wind speed is small in the cutting，but it the mostly easily causes the wind snow drift． The deeper the cutting is，the larger the scale and scope of scroll deceleration zone are at the toe of the cutting slope in the upper wind direction，the bigger the critical storage of snow on the slope is，the relatively slower the process of the blizzard flow disasters is． The more slowly the slope is，the smaller the scale and scope of scroll deceleration zone are． The moderate slope can reduce the snow － drift of subgrade surface，but it doubles the engineering quantity． To consider two aspects of engineering security and economic benefits，the rate of slope should be chosen by taking other snow damage control measures into account ．