The temperature effcet on ground state binging energy strong-coupling polaron in a symmetry quantum dot are studied by using an linear combination operator and the unitary transformation methods. The relations of the ground state binding energy of the polaron with the effective confinement strongth and temperature,and the mean number of phonon with the coupling strength were derived. Selecting RbCl quantum dot,numerical calculations are performed and the results show that the ground state binding energy will increase with decreasing the effective confinement strongth,whereas the ground state binding energy and the mean number of phonon will increase with increasing temperature. Selecting different quantum dots,the mean number of phonon is an increasing function of coupling strength and temperature.