Surface properties of epitaxially grown PbTe(1 1 1) thin films on BaF2(1 1 1) substrates were systematically investigated by the characterizations of in situ reflection high energy electron diffraction (RHEED) and atomic force microscope (AFM). First principal calculations were performed to facilitate the interpretation of experimental observations. Our results indicate that substrate temperature (T-sub) and chemical environment are crucial in determining the type of surface structure during the growth of PbTe(1 1 1) thin films. When PbTe is grown at T-sub = 250 degrees C, the metastable (1 x 1) structure is formed on the PbTe( 1 1 1) surface. However, whether T-sub is elevated to 300 degrees C or the PbTe( 1 1 1)-(1 x 1) sample grown at T-sub = 250 degrees C is post-annealed at 300 degrees C, the stable (2 x 1) reconstructions appear on the PbTe(1 1 1) surface. In Pb-rich environment, the most stable (2 1) reconstruction results from the substitution of the half of the 2nd Te atoms by Pb atoms, while in Te-rich environment, the most stable (2 x 1) reconstruction originates from the missing of half of the 1st Pb atoms. (C) 2015 Elsevier B.V. All rights reserved.