In recent years, freezing construction method has been increasingly used in urban civil engineering construction; however, due to the insufficient theoretical basis on permafrost freezing and the limitation of research methods, the ideal scheme for freezing method design has not been found for a long period of time, great difficulties were encountered in parameters variable selection. And there were no relatively unified technical standard as reference in the construction, which causes large engineering quantity waste and construction chaos with no quality assurance for this construction method. Freezing tube diameter is the main influencing parameter. Through the research on the soil freezing tests in coaxial tubes of different tube's diameter, the distribution law of temperature field in the freezing process was analyzed by using Fluent model, the selection method for optimal freezing tube diameter is finally determined, which provides the basis for the design and construction of the freezing method.