Clayshale and siltstone are types of sediment that generally defined as mudrock. It’s refer to a kind of sedimentary rock that formed from fine grained material, for instance, clay or silt. Mudrock has high level of hardness, however, the disadvantage of mudrock is the durability of hydrosphere and atmospheric exposure that considered very low. This often become an obstruction during the construction process in the field. Cement stabilization is one of the ways to increase the bearing capacity and durability against weather cycle. Furthermore, most studies in the field of mudrock stabilization tehniques have only focused on dry pulverizing. This research set out to investigate the effectiveness of cement stabilization and the mixing method on clayshale and siltstone. To determine the soil compressive strength, unconfined compression strength test performed using specimen with 10% amount of cement corresponding to its dry unit weight. Atterberg limit test also performed in order to identify the influence of cement addition on plasticity index. The results of this investigation show that after stabilization, all specimen have decreased on liquid limit and increased on plastic limit, which caused a decrement on mudrock plasticity index. The unconfined compression strength increased significanly on clayshale and siltstone specimen In summary, these results show that specimen prepared using spray mixing method indicate higher unconfined compression strength and lower modulus of elasticity compared to specimen prepared using dry mixing method.