The hydrokinetic energy conversion system has capabilities to supply inevitable and secured power which is obtained from free stream like ocean, river, and man-made channel etc. So far, researchers have done different work on resource availability, design parameter, electricity generation cost, reactivity of plant, its impact on environmental separately. In this paper an attempt is made to review the technology, performance, design optimization, reliability, techno-economic analysis and environmental impact of the hydrokinetic energy conversion systems altogether to establish the relationship between the above said aspects towards the viability of power project. After conducting these reviews it has become clear that in order to avoid cavitation, coefficient of pressure should be less than cavitation coefficient especially at leading edge of hydrokinetic turbine blade. Moreover, to avoid stall and separation, angle of attack should be kept as less as possible. By implementing hydrofoil blade profile, performance of the hydrokinetic turbine can be improved. Sometimes, implementation of double blade hydrofoil may be beneficial and increase the coefficient of lift more than that of the single blade hydrofoil. Apart from the above considerations it is to be noted that deployment of turbine near bed level should be avoided as it brings down available power, increase hydrodynamic loading, turbulence level, and fouling by sediments. Moreover to increase the performance arm and end plate can be incorporated in hydrokinetic turbine design. It is also observed that hybrid conversion system is also viable in order to reduce power generation cost. This paper will help researchers to identify areas of design parameter of hydrokinetic turbine that need to improve and encourage the project developer, funding and financial institution, policy maker or government officials, and local community, to provide knowledge about hydrokinetic energy conversion system for executing the project and compete with the existing market.