Within the framework of QED theory at finite temperature, the thermal radiative corrections to spontaneous one-photon transition rates in hydrogen atom are investigated. The radiative one-loop self-energy corrections are described in the thermal case. Closed analytical expressions are derived and their numerical calcul- ations for the spontaneous decay rate of the 2p state are carried out. The dominance of thermal radiative corrections to a spontaneous Lyα decay rate over an ordinary induced transition rate up to temperatures T<6000 K is demonstrated.