Abstract: Contaminant transport through liners was analyzed often with deterministic methods.In order to study the impact of spatial variability of hydraulic conductivity on contaminant transport, random field theory of soil profile was used.With hydraulic conductivity being modeled as a lognormal distribution random field, Monte-Carlo method and numerical integrating were used to analyze probabilistic characteristic of contaminant transport.Results from the two methods are of good compatibility.Spatial variability of hydraulic conductivity is very important for contaminant transport through liners.With the increase of variability, failure probability decreases in the late phase, but the probability of very high concentration at the base of liner will increase.The variability and range of hydraulic conductivity will affect the reliability of liner.