• Synthesized the MgZnO nanoparticles by changing the copper and zinc content using a hydrothermal method. • Growth of MgZnO nanoparticles and confirmed the pure and secondary phase formation by XRD, Raman. • The grain size of the MgZnO composite decreases by variation of atomic mole concentration of Mg and Zn. • The thermoelectric performance increase via string chemical bonding and energy filtering effect at the grain boundaries. We are developing novel n-type thermoelectric materials that are extremely efficient and processable. In this article, we have reported the fabrication of MgZnO nanoparticles using a hydrothermal method. The impact of Mg and Zn content on the structural and thermoelectric properties of MgZnO nanoparticles has been investigated. The X-Ray diffraction analysis of MgZnO has revealed the presence of the hexagonal wurtzite structure phase with planes (1 0 0), (1 0 2), (2 0 2), (1 1 0), and (1 1 2). The best crystallinity has obtained for the Mg 0.5 ZnO sample at lower content of Mg in the basic hexagonal structure. As the atomic composition changes, all atoms get additional energy, and the crystal structure shifts accordingly. The Raman spectrum has confirmed the pure hexagonal wurtzite structure of MgZnO with different orders of the A 1 (LO) modes. The Seebeck coefficient and electrical conductivity have increased with changing the different content of Mg +2 and Zn +2 atoms. We have achieved the maximum power factor of 7.58 μWm -1 C -2 in the sample Mg 0.5 ZnO. The work demonstrates that a synergetic increase in thermoelectric properties may be accomplished by increasing chemical bonding and forming ionic blocking layers at the grain boundary.