The invention discloses a method for detecting the stability of a temporary bracing structure, comprising the following steps: applying a horizontal force on one side at the top part of the temporary bracing structure, and calculating a sidewise displacement value at the top end thereof by using a planar structure calculation software; applying a force which is the same with the horizontal force of the temporary bracing structure at the top end of a cantilever mast with the completely same boundary condition and height, calculating the sidewise displacement at the top end of the cantilever mast according to the known calculation formula of the cantilever mast sidewise displacement value, and calculating the critical load of the cantilever mast by the calculation formula of the critical load value of the cantilever mast stability; calculating the correlation coefficient of the sidewise displacement value at the top end of the temporary bracing structure and the sidewise displacement at the top end of the cantilever mast; and determining the critical load value of the stability of the temporary bracing structure. A test for measuring the horizontal displacement and the horizontal concentrated force of the temporary bracing structure can be used for replacing the test for detecting the stability of the temporary bracing structure which are difficult to realize, thus the invention can judge the stability of the temporary bracing structure by a simple method.