Abstract: Mo and its alloys were selected as candidate structural materials for hightemperature applications because of many attractive properties like outstanding heatconducting capabilities and hightemperature strength. However, the inherent embrittlement of Mo at and below ambient temperature severely limits the application of molybdenum and Mobased alloys as cladding materials. This weak point is generally considered to be caused by several factors, and one of the important factors is that the Mo grain boundary itself has low strength and is easy to become the preferred location for crack nucleation and propagation. In order to systematically understand the grain boundary structure of pure Mo, the grain boundary energy and vacancy formation energy of 32〈110〉 symmetric tilt grain boundaries were studied by molecular statics method, and the formation regularity of vacancy at grain boundaries was discussed. For grain boundary energy, the results calculated by four interatomic potentials are generally higher than previous study but the trend is nearly the same. Only a few grain boundaries, such as Σ3(111) and Σ3(112) grain boundaries, are inconsistent with the trend. For vacancy near the GB, the vacancy formation energy calculated by MEAM and ADP potential functions are 2.95 eV and 2.97 eV respectively, which are in agreement with results calculated by density functional theory (DFT). However, the results calculated by EAM and SNAP are slightly lower, which are 2.65 eV and 2.58 eV. For the formation regularity of vacancy, the results show that vacancies are more easily formed in the grain boundary than in the perfect crystal, and the vacancy formation energy in the grain boundary is closely related to the grain boundary energy, and the more stable the grain boundary is, the less prone to form vacancies. There are significant differences in the formation regularity of vacancies in different grain boundary structures. In the grain boundaries with tilt angle less than or equal to 58.992°, vacancies are easy to form in the C structure units. For the grain boundaries with tilt angle between 58.992° and 144 364°, vacancies are easily formed in the “roof” structure. For the grain boundaries with tilt angle greater than 144.364°, vacancies are easily formed in the Z structure. In addition, the results of 32 grain boundary structures calculated by four interatomic potentials show that there is no significant difference between the four potentials in terms of grain boundary energy and vacancy formation energy, but some grain boundary structures relaxed by SNAP potential function have higher asymmetry.