Bismuth trioxide (Bi2O3) is an oxygen ion conductor. In order to obtain its atomic thermal vibration isotropic temperature factor, X-ray diffraction experiments were carried out on the powder crystal, and the crystal structure model was established. The RIETAN-2000 program refined the crystal structure of the obtained experimental results, and obtained the three-dimensional (3D) and two-dimensional (2D) visualization patterns of the powder crystal’s iso-high electron density distribution through MEM analysis. The results show that the atomic thermal vibrational isotropic temperature factors of Bi(1), Bi(2), O(1), O(2) and O(3) are 0.004 938 nm2, 0.004 174 nm2, 0.007 344 nm2, 0.007 462 nm2, and 0.007 857 nm2，respectively. The three-dimensional and two-dimensional visualization of the electron density distribution at the same height further verifies the accuracy of the crystal structure model and the position of atoms. These parameters have a certain reference significance for studying the thermal properties of crystal materials.