Influence of external magnetic field, longitudinal-optical (LO) phonon effect and thickness of quantum disks (QDs) on the properties of electron-LO phonon strong-coupling magnetopolarons and the qubit is studied by using Lee -Low-Pines-Huybrechts variational method. The expressions for the mean number of phonons of magnetopolarons , electron-LO phonon interaction energy E (e-ph), energies of the ground and first-excited states E (0) and E (1), oscillation period T (0) of qubits and probability distribution rho of electrons are derived. Results of numerical calculations show that the mean number of phonons of the ground state of magnetopolarons is larger than that of the first-excited state, the mean number of phonons of magnetopolarons increases with increasing the cyclotron frequency omega (c), confinement strength omega (0) and coupling strength alpha, but decreases and oscillates with increasing the thickness of QDs L; E (e-ph) is always negative, a E pound (e-ph)a pound of the ground state is larger than that of the first-excited state, and a E pound (e-ph)a pound increases with increasing omega (c), omega (0) and alpha but decreases with increasing L; E (0) and E (1) increase with increasing omega (c), omega (0) and alpha, but decrease with increasing L; T (0) increases with increasing omega (0) and L, but decreases with increasing alpha; rho decreases and oscillates with increasing L, and decreases with increasing omega (0); the variations of T (0) and rho with omega (c) and L are influenced by omega (0) and alpha significantly.