The　influence　of　PTFE　vapor　injected　into　the　SF6　on　dielectric　strength　of　hot　gas　mixture　which　corresponds　to　the　dielectric　recovery　phase　of　a　high　voltage　circuit　breaker　are　investigated　in　the　temperature　range　from　300K　to　3500K.　The　equilibrium　compositions　of　hot　SF6/PTFE　vapor　mixture　were　determined　based　on　Gibbs　free　energy　minimization.　Additionally,　adopting　full　sets　of　improved　cross　sections,　the　critical　reduced　electric　field　strength　of　this　derived　composition　was　obtained　by　a　balancing　electron　generation　and　loss　modeled　by　the　interactions　between　electrons　and　the　dissociated　species　of　hot　gas　evaluated　by　the　electron　energy　distribution　function　(EEDF)　derived　from　the　Boltzmann　transport　equation.　Results　indicates　that　above　the　temperature　of　2500K,　the　addition　of　PTFE　vapor　leads　to　a　higher　critical　breakdown　field　which　is　an　important　result　for　practical　applications.