Abstract: The design theory of frozen soil wall is one of the core technologies for mine shaft freezing sinking. The conventional elastic design formula for the thickness of frozen soil wall has large errors in case the modulus ratio of frozen soil wall to surrounding rock is less than 10. Taking into account the effect of excavation unloading and the interaction between frozen soil wall and surrounding rock, a more practical mechanical model is established for a more rational design of frozen soil wall. Its analytical solutions of elasticity are derived. The variation laws of stresses and displacements in frozen soil wall and surrounding rock are analysed. The design methods for the thickness of frozen soil wall are discussed. Based on Tresca strength condition and Mises strength condition respectively , two new elastic design formulae for the thickness of frozen soil wall are put forward. Analyses and comparisons show that the proposed formulae are more reasonable and more economical than the traditional elastic design formula for the thickness of frozen soil wall.