The hybrid OTEC (H-OTEC) cycle is a system integrating a desalination and an OTEC which generates power using the temperature difference between the surface and depth in the ocean. The system is, therefore, able to produce the electric power and the distilled water from seawater, simultaneously. The cycle uses low pressure steam as warm heat source generated by the flash evaporation in vacuumed condition instead of flowing the surface seawater, which acquires: to prevent the performance degradation of the evaporator caused by the fouling due to marine organisms; to improve the heat transfer and to cost reduction by using the stainless steel instead of the titanium for an evaporator. In this study, the effects of mass flow rate of working fluid in the hybrid cycle were clarified by a parametric analysis. For the evaluation of the system, not only the conventional thermal efficiency but also the normalized thermal and exergy efficiencies, which is proposed based on the equilibrium state of heat sources, are introduced. As the results, it is confirmed that the net power generation increases with working fluid flow rate, while the product flow rate of desalinated water increases with working fluid flow rate. Moreover, the specific power consumption decreased significantly by increment of working fluid flow rate.