Abstract: The weighing method is adopted in condensation of the water observation.The condensation water for the different kinds of soil samples are observed during the freezing period and non-freezing period respectively.The necessary conditions and time occurring the condensation water,the main influence factors forming the condensation water,the condensation water under the accumulated snow circumstances,the amount of the condensation water and its variation,and the eco-environmental significance of the condensation water are all analyzed and discussed.The research achievements have great significance to recognize the formation mechanism of the condensation water and the eco-environmental benefit of the condensation water in the arid areas,NorthwesternOTina.