Abstract: It is difficult to produce viscous oil by using conventional methods because it features in high viscosity and density,but low displacement efficiency.So research is conducted on developing pumping and producing devices.The heating function of the fully hydraulic thermal exploiting system for viscous oil is introduced with its fluid and heat transfer of the bottom hole fluids being analyzed.The physical and mathematical models of the bottom hole fluids with the heat transfer are established,analyzed,and rectified.With the oil well practice parameter and flux,temperature of the hydraulic oil input,the theoretical equation of the heat transfer and models which have been achieved are improved based on simulating the relationship of the heat transfer in the bottom hole on computer.Moreover,the relationship between the viscous oil output and the hydraulic oil input is derived,so does the minimal input of hydraulic oil which is needed by keeping temperature and producing viscous oil.The models developed also provide a theoretical basis on which the heat transfer of bottom hole fluids in the different holes and with the different import state will be studied further.