finite temperature we construct a new thermal excitation representation |E,g>, which is the common eigenvector of Hamiltonian operator of total system (including the reservoir) and the operator (α(β)−ã†(β))(α†(β)−ã(β)), where α†(β) (ã†(β)) creates a quantum of energy hω(β) (−hω(β)), respectively, β=ãh/kT, k is the Boltzmann constant. The explicit from of |E,g> is derived by virtue of the common eigenvector α(β)− ã†(β) and α†(β)− ã(β). The thermo excitation and de-excitation operations are manifestly displayed in |E,g> representation. As an application, the |E,g> representation of thermal squeezing operator is obtained.