Abstract: The application of cement-stabilized mud (CSM) as the filling materials of embankments mitigates the issue of local scarcity of ideal filling materials (e.g., sand and gravel) and allows significant volumes of unwanted mud arising from dredging to be disposed economically and ecologically. Nevertheless, this artificial material tends to show very high spatial variability in engineering properties. The high spatial variability can produce substantial influences on the stability of CSM embankments, but is not well considered in the conventional deterministic design method (CDDM). In this study, the statistical information of the engineering properties of in-situ CSM is first identified, and the random fields characterizing the spatial variability of these properties are generated. Both deterministic and random field numerical simulations are then performed to analyze the stability of a number of typical CSM embankments. Special attention is paid to compare the difference between the CDDM and the random field method. The results show that the effect of spatial variability is significant but not reasonably accounted for in CDDM, very probably leading to unsafe design for CSM embankments. Finally, an empirical formula is proposed to describe the relationship amongst the safety factor of stability in CDDM, the embankment design parameters, the coefficient of variation for CSM strength, and the reliability index. This empirical formula can be adopted to equivalently characterize the influences of spatial variability on the stability of CSM embankments, without changing the framework of CDDM.