The environmental issues combined with the rising of crude oil price have attracted more interest in waste heat recovery of marine engine. currently, the thermal efficiency of marine diesels only reaches 48∼51%, and the rest energy is rejected to the environment in forms of exhaust, cooling water and so on. Meanwhile, energy is required when generating electricity and cooling that are necessary for vessels. Hence, the cogeneration system is treated as the promising technology to conform the strict environment regulation while offering a high energy utilization ratio. In this paper, an electricity and cooling cogeneration system combined of Organic Rankine Cycle (ORC) and Absorption Refrigeration Cooling (ARC) is proposed to recover waste heat from marine engine. the ORC is applied to recover exhaust waste heat to provide electricity while APR is used to utilize condensation heat of ORC to produce additional cooling thus to improve thermal efficiency of WHR system. Four typical alkane (benzene, toluene, cyclohexane and cyclopentane) is selected as ORC working fluid. Simulations were performed at different evaporating pressure, condensing pressures and superheat degree of ORC. Results shows that the superheat degree almost have a negative effect on the electricity output, cooling capacity and exergy efficiency. The highest primary energy ratio of WHR system can be obtained when the condensation temperature of ORC is 130℃. Higher exergy efficiency can be achieved for the proposed cogeneration system than basic ORC. Among the four alkanes considered, comparisons show that the most promising candidate are benzene and toluene. The former is suitable for high evaporation pressure system with a highest exergy efficiency of 51.7%, and the latter is potential for low evaporation pressure system with a highest exergy efficiency of 48.3%.