Under the effective mass approximation

the internal excited state properties of the strong-coupling exciton in polar crystals quantum dot are studied by using linear combination operator and unitary transformation methods. The ground state energy

the first internal excited state energy and the excitation energy in the strong-coupling polar crystals quantum dot as a function of the quantum dot radius are obtained. Numerical calculations for TlCl crystal show that the ground state energy

the first internal excited state energy and the excitation energy of the strong-coupling exciton will increase strongly with the decreasing of the quantum dot radius.