In this paper, we first introduce Ket-Bra entangled state method to solve master equation of finite-level system, which can convert master equation into Schrdinger-like equation and solve it with the mature methodology of Schrdinger equation. Then, several physical models include a radioactivity damped 2-level atom driven by classical field, a J-C model with cavity damping, a V-type qutrit under amplitude damping and N-qubits open Heisenberg chain have been solved with KBES method. Furthermore, the dynamic evolution and decoherence process of these models are investigated.