In the present paper, we investigate the effect of polaron on the thermodynamic properties of an asymmetric semiconductor quantum wire under magnetic field. We used the Grand canonical ensemble approach to determine the thermodynamic properties such as: entropy, heat capacity and free energy and some magnetic properties as magnetization and magnetic susceptibility. We have shown that the effect of confinement potential and the application of an external magnetic field increase the energy in the asymmetric quantum wire, for the lowest values of the magnetic field, entropy and heat capacity increase with temperature after their saturation for the same value of the magnetic field they become independent of temperature. It was also found at high values of the temperature the magnetic susceptibility becomes independent of the magnetic field. It has been found that for a magnetic field almost equal to 1 or 1.2 T the entropy as well as the heat capacity reaches their saturation then become independent of the temperature. The diamagnetic aspect of our system allows to extend its scope both in electronics (manufacturing of transistors, energy storage structures, etc.), in industry (the realization of magnetic levitation trains) in medicine (magnetic resonance imaging MRI).