The freezing process of artificial frozen soil is divided into thermal loss of soil surface and freezing of freezing pipes; and the relationship between freezing influencing range and freezing time is analyzed by thermal potential and equilibrium equation of thermal potential consumption process. And then, the thermal potential theory is introduced; the equivalent thermal resistance is calculated; the freezing time equation of micro unit under impact of multiple freezing pipes is established; and the calculation method for relationship between freezing influencing range and freezing time and the deciding method for spacing between freezing pipes are proposed. Finally, the calculation method for the depth of artificial frozen soil is analyzed by case studies; and the influence of different spacings between freezing pipes on freezing times is compared by numerical simulation method. The study results can deepen the relationship between theoretical study and practice of artificial frozen soil.