The measured coefficient of consolidation can have a substantial degree of variation even in a uniform clay layer. This paper examines the variability of one-dimensional consolidation solutions through a probabilistic analysis. The spatial probabilistic characteristics for the coefficient of vertical consolidation are studied. The influence of a spatially random coefficient of consolidation on one-dimensional consolidation has been studied using the probabilistic method. In the probabilistic analysis, the adequacy of distribution model for coefficient of consolidation is tested using experimental data. A sensitivity analysis of the degree of consolidation to uncertain parameters is presented for clay soil. It is the analysis result that probability distribution type of vertical consolidation has a considerable influence on degree of consolidation. The results are discussed in terms of confidence level.