Two kinds of aromatic polyesters containing thioether units had been prepared through the reaction of 4,4'-thiodibenzoyl chloride (T-DC) (or 4,4'-bis(4-chloroformylphenylthio)benzene (BPBDC)) and 1,1-bis(4-hydroxyphenyl)-1-phenylethane (BHPPE) by the method of interfacial polycondensation. These polyesters showed good solubility, and could afford tough films with tensile strengths of 103.6-108.3 MPa. The glass transition temperature (T-g) of these polyesters ranged from 189.8 to 235.6 degrees C and initial degradation temperatures (T-d) were 450-454 degrees C. The activation energies of degradation were in range of 156.6-160.3 KJ/mol. The limiting oxygen indexes (LOIs) of these polyesters ranged from 37 to 39, and UL-94 V-0 rating could achieve via this approach. The thermal degradation kinetics and thermal pyrolysis mechanism of these polyesters was studied by thermogravimetric analysis and Py-GC/MS analysis, respectively.