Based on the theory of the probability interpretation algorithm，a statistical model of RLC interconnect delay in the presence of process variations was put forward. This model adopted the Lognormal Distribution Function. By this arithmetic，only the first two moments were needed to estimate the interconnect delay. Compared with HSPICE，the average errors of the mean and average deviation in Monte Carlo analysis were less than 0.7% and 0.51% respectively. The model of this paper is of simple calculation and high precision，which can satisfy the requirement of interconnect simulation.