An analytical investigation has been conducted to understand the internal fluid flow andheat transfer in the condenser with porous wick of an innovative capillary pumping loop (CPL) system.A mathematical model is proposed and used to descdbe the flow and heat transfer, especially interra-cial transport phenomena. The liquid-vapor interface of the condensed liquid film was numerically deter-mined. Some factors, such as vapor pressure, wall subcooling, wall heat load and thermofluid proper-ties, have significant influence on the heat transfer process and the shape of liquid-vapor interface.Meanwhile, an experimental facility was setup and an experimental investigation was completed. Theo-retical prediction and experimental results show quite good consistence.