  In the YBa2Cu3O7-{\delta} (YBCO) high temperature superconducting thin film
fabrication via the chemical solution deposition method, BaF2 is an important
intermediate phase during heat treatment. In this paper, BaF2 thermodynamics
stability was analyzed through calculating the standard Gibbs free energy
change ({\Delta}GT) of the reactions related to other intermediate phases
within the temperature range of 700-1000 K. Two thermodynamics methods, the
Gibbs free energy function method and standard formation molar Gibbs free
energy method, were utilized to obtain the {\Delta}GT values. The formation
priority of BaF2 relative to other intermediate phases were verified at higher
temperatures, while the possibility of BaCO3 formation was found at 700 K.
