Aiming at the problem that the reliability index calculated by the traditional reliability design method in the foundation reliability analysis is undersized and the failure probability is oversized，we apply the random field theory to the foundation reliability analysis. Combining with a large number of geological exploration data obtained in the process of building the green petrochemical base in the Yushan area，we discuss the rationality of determining the correlation distance of soil layer by improved recursive space method based on random field theory，count the correlation distance and variance reduction function value of the typical soil layer in this area，and apply it to the reliability analysis of slope stability. The results show that the application of random field theory to the analysis of foundation reliability has an important promotional value. The improved recursive space method is easier to determine the correlation distance value of soil property indexes，and the reliability index obtained by variance reduction of foundation soil strength indexes cohesive force and friction angle is more in line with the safety degree of engineering practice.