The conventional port distribution power system is being disrupted by increasing distributed generation (DG) levels based on integrated energy. Different new energy resources combine with conventional generation and energy storage to improve the reliability of the systems. Reliability assessment is one of the key indicators to measure the impact of the distributed generation units based on integrated energy. In this work, an analytical method to investigate the impacts of using solar, wind, energy storage system (ESS), combined cooling, heating and power (CCHP) system and commercial power on the reliability of the port distribution power system is improved, where the stochastic characteristics models of the major components of the new energy DG resources are based on Markov chain for assessment. The improved method is implemented on the IEEE 34 Node Test Feeder distribution power system to establish that new energy resources can be utilized to improve the reliability of the power system. The results obtained from the case studies have demonstrated efficient and robust performance. Moreover, the impacts of integrating DG units into the conventional port power system at proper locations and with appropriate capacities are analyzed in detail.