Abstract: The researches on the stability of slope by strength reduction mainly refer to homogeneous slopes, however, when the inhomogeneous slopes are met, some questions will come forth, the scope of strength reduction is global or local region? In view of the above, the global strength reduction and the local strength reduction are programmed in this paper by FISH in the FLAC3D, and the inhomogeneous slopes are analyzed. The results show that the safety factors of inhomogeneous slope solved by these two methods are not always equal and the factor of safety computed by global strength reduction is more reasonable and more precise, so it is advised that the global strength method is better than the local strength method when the inhomogeneous slope is analyzed.