We analyze the dynamic localization of two interacting electrons induced by alteating current electric fields in triple quantum dots and triple quantum dot shuttles.The calculation of the long-time averaged occupation probability shows that both the intra-and inter-dot Coulomb interaction can increase the localization of electrons even when the AC field is not very large.The mechanical oscillation of the quantum dot shuttles may keep the localization of electrons at a high level within a range if its frequency is quite a bit smaller than the AC field.However,the localization may be depressed if the frequency of the mechanical oscillation is the integer times of the frequency of the AC field.We also derive the analytical condition of two-electron localization both for triple quantum dots and quantum dot shuttles within the Floquet formalism.