Ocean Thermal Energy Conversion (OTEC) is a promising sustainable energy technology, usually based on organic Rankine working fluids for conversion. In this paper, a variety of working fluids are used to evaluate organic Rankine cycle (ORC) applications for OTEC. The steady model of organic Rankine cycle is established to analysis the performance which is classification according to isentropic type of working fluids. The result show R32 has the highest thermal efficiency, with a thermal efficiency of 3.52%, and R1234yf, R125 and r143a have high thermal efficiency, which are environment-friendly and isentropic, and are suitable for organic Rankine cycle power generation.