The excitation in actual circuits is always nonideal, which has a definite impact on the analysis of interconnect delay. Considering the impact, the analytical delay model is proposed and the analytical delay method based on coupled RLC interconnect is presented. Then the decoupling method is improved and the coupled interconnects model under ramp input is decoupled when analyzing the interconnect segments. Finally the two-pole model is combined with the improved modified one-pole model to simplify the transfer function and the expression of delay of coupled interconnects is proposed. Experimental results demonstrate that the analysis method can evaluate the delay of coupled RLC interconnects effectively.