Abstract: With the analysis of the characteristics of the Capillary pumped Loop (CPL) during steady operation, it is concluded that the heat transfer mode of the inverted meniscus type evaporator, in this case, is surface-evaporation. In addition, the method to calculate the vapor flow resistance in the wick of the inverted meniscus type evaporator is also presented. With this method, the calculation of an actual CPL model is carried out, and it is obtained from the analysis that the vapor flow resistance in the wick should be taken into account during the CPL's design. Additionally, it is also known that the permeability of the wick has a great effect on the resistance.