The strength of cement-treated soil varies greatly owing to variability of the in-situ soil, variability of mixing effectiveness, and other factors. This paper presents the numerical experiments that investigate the effect of the spatial correlation on the behavior of cement-treated soil columns with different sizes. Finite element analyses were performed to simulate the unconfined compression behavior of the columns with three different heights. The spatial distribution of the material properties was provided by means of Monte Carlo simulation. The simulations were carried out with the samples in the presence of different degrees of spatial autocorrelation. The numerical results provide good understanding of the effects of the column height on the compression behavior of the cement-treated soil columns with spatial variability.