Abstract: Dredged filling as a low-cost, pollution-free, double-effective method of land reclamation, has been widely applied in the offshore areas. Then, the improvement of double-layered ground composed by dredged fill and marine mud has been becoming a hot spot concerned by geotechnical engineers. The probability and statistics theory is introduced into the analysis of the double-layered sand-drained ground consolidation. The influences of the uncertainty of geotechnical parameters and the correlative distance of soil are studied. Under the horizontal coefficient of consolidation being a gamma distribution, the computational formulas of the expectation and variance of consolidation degree for double-layered sand-drained ground are obtained. The Monte Carlo simulation method is used to analyze the average consolidation degree for double-layered sand-drained ground in a project in Shenzhen. The results show that the preloading time calculated by the deterministic method can not meet the requirements of the project, and the probabilistic analysis is more reasonable.