Abstract: Heat pipe cooled reactor has the advantages of simple structure, passive heat transfer and high reliability, owning to the design of solid reactor core and heat transfer using high-temperature heat pipe. In order to study the transient and safety characteristic of space heat pipe cooled reactor with thermoelectric conversion, the detailed mathematical and physical models were established for the most key system of the reactor including the reactor, high temperature heat pipe, thermoelectric conversion system. The reactor model was developed by coupling point-kinetic model, reactivity feedback model and power distribution model based on OpenFOAM, in which three different interface heat transfer models were developed to couple different regions in solid reactor. The reactor model overcome modeling difficulty of some typical accident scenarios such as heat pipe failure accident, the actual distribution and variation of temperature can be accurately obtained. The two-dimensional transient heat pipe model was present which was suitable for transient simulation of high-temperature heat pipe after startup. The transient working condition of a sodium heat pipe was simulated, the result fits quite well with the thermal resistance network model and two-dimensional model. For the thermoelectric generator, the one-dimensional transient model was established, in which the effect of Peltier heat, Fourier's heat conduction, Joule heat and Thomson heat was considered, the dynamic behaviors of thermoelectric generator under different thermal conditions can be simulated. In order to testify the thermoelectric generator model, a BiTe-based thermoelectric module was built and verified with the experiment data under two different working conditions. The output electric power deviation compared with experiment data is 2.47% and 2.75% under two working conditions. The transient system analysis program for thermoelectric space heat pipe cooled reactor was developed and fully verified with the experimental data of the KRUSTY prototype reactor. The detailed KRUSTY reactor model was established in the program, the accident conditions of the KRUSTY were calculated including reactivity control, thermoelectric conversion module failure, loading following and active heat removal accident. The results show that the simulation results of program are in good agreement with test data, the max deviation of surface fuel temperature is less than 4.1 K under these accident conditions and the accuracy of the model is proved. The program will provide effective analysis and research tool for the transient characteristic study of space heat pipe cooled reactor with thermoelectric conversion.