The brick-wall model is widely used to calculate the entropies of static or stationary black holes. An ultraviolet cutoff factor needs to be introduced to remove the divergence of the result in brick-wall model. The cutoff factor has not been explained reasonably up to now. A study indicated that when the brick-wall model or thin film model was used to calculate the black hole entropy, the ultraviolet cutoff factor could be discarded if the generalized uncertainty relation was adopted. In this paper, it is proved that since the first term of Schwarzschild black hole entropy formula in the brick-wall model is not only the Bekenstein-Hawking term but also the term containing the ultraviolet cutoff factor, when the cutoff factor is removed, the Bekenstein-Hawking term is lost and the black hole entropy cannot be obtained by using the generalized uncertainty relation in brick-wall model.