In this paper the role of Plug-In Electric Vehicles’ (PIEVs) parking lot in operating Smart Multi-Energy System (SMES) has been investigated. SMES in this paper has been modeled as a multi-input multi-output model which consists of some storage and energy converters. In the proposed framework, the PIEV’s parking lot behaves like an energy storage with selling energy price less than upstream network price and as manageable load when its purchase price is more than upstream network. On the other hand, traffic pattern of PIEVs in parking lot has an uncertain behavior and is modeled based on stochastic approach. In the stochastic model, two branches of scenarios for total state of charge and total capacity of parking lot in each hour are produced. The considered case studies show the effectiveness of the proposed model and the impact of PIEVs’ parking lot in operation of SMES elements.