Abstract: Three-dimensional,continuous energy Monte Carlo code（MCNP） is adopted to carry out the analysis of zero power experiment of HFETR.From the results,the impurity,density of Beryllium block and the ¹⁰B concentration in control rod transition part should be carefully determined in the analysis of zero power experiment.While in the experiment of HFETR,the Beryllium block is considered as pure metal and the ¹⁰B concentration in control rod transition part is different from that of zero power experiment.From the calculation results,these parameters（effective neutron multiplication factor k_eff,relative distribution of neutron flux density,γ dose rate distribution and component reactivity） are quite fit with the experiment.The difference of small reactivity between calculation and experiment is quite large,and may be related to the deficiency of MCNP model.