A cable-braced grid shell is a new type of single-layer latticed shell suitable for glass roofs. Compared with traditional single-layer latticed shells, this new type of shell has a unique mesh shape (planar quadrilateral mesh), mesh form (steel and crossing cables), and surface shape (from the translation surface method). The grid shell is a single-layer latticed structure, and therefore stability is one of the key factors in the structural design. Therefore, in this paper, an elliptic paraboloid cable-braced grid shell with imperfections is used as an example with which to determine the formulas for the buckling load based on the continuum analogy. The main contents of this paper include the formula for the linear buckling load of an elliptic paraboloid cable-braced grid shell with imperfections, which is determined based on the continuum analogy. The equivalent rigidity for the cable-braced grid shell is then determined, and the effect of the cables on the shear rigidity is discussed. Finally, the formula for the linear buckling load is verified with numerical examples, and the errors are analyzed and a corresponding correction factor is given.