The two-level atom is described by Pauli sign and the environment is described by infinite harmonic particle thermal reservoir. We have studied the problem of fidelity of quantum states of two-level atoms located in strongly thermal radiation field. The two-level atoms' reducible density rectangular array is obtained. We discuss the properties of fidelity. It is shown that for the two two-level atoms initially situated in different coherent superposition states, quantum information may partly lose fidelity or may not lose fidelity during evolution in transmission process.