Abstract: Separated heat pipe has been applied in the industrial field, and is mostly applied in energy-saving field such as waste heat recovery boilers, because of its advantages such as fully separation of hot surface and cooling surface, completely isolation of heat source and cold source, and high heat exchange efficiency. Based on the working characteristics of the separated heat pipe, the passive residual heat removal system based on the heat pipe was developed. The theoretical design of the residual heat removal system is analyzed and demonstrated based on the system program. The parameters on the performance of the heat pipe is obtained including the different liquid charging rates, the elevation difference between heat source with cold source and the condensation section area ratio. When the liquid charging rates is larger than 0.7, the heat transfer power of the system decreases obviously. Even without the elevation difference between heat source with cold source, the system still can build the convection. The heat transfer power of the system increases proportionally with the increasing of the condensation section area ratio, when it ranges from1.0 to 2.5.