Effect of the electron-phonon interactions on the property of dynamical localization of semiconductor superlattices in a single-band model under the actions of the dc and ac electric field, respectively, is investigated. The results show that the electron-phonon interactions can destroy the dynamical localization of the electron. For the same phonon frequency, when the strength of the electron-phonon interactions becomes larger, the electron is more quickly scattered.When the phonon frequency equals to the Bloch frequency ΩB in dc field or ω in ac field or one of them in dc-ac field,the electron initially localized at the 0th site can be rapidly scattered to the other sites, where ω is the frequency of the ac field. The property of the dynamical localization of the electron can be seriously changed by the photon-phonon resonant field.