There is an urgent need to develop magnesium-matrix materials that exhibit both high thermal conductivity and low thermal expansion to ensure compatibility with chips. This study aims to develop a Mg-Zn-Cu alloy with high thermal conductivity. Furthermore, it explores the preparation of AlNP/Mg-Zn-Cu composites featuring low coefficients of thermal expansion. The stir casting method was utilized to fabricate the composites and an investigation was conducted to examine their microstructure and thermal properties. Results indicate that the addition of AlNP reduces the thermal expansion coefficient while maintaining relatively high thermal conductivity. Specifically, the AlNP/Mg-0.5Zn-0.5Cu composite with 30wt.% AlNP achieves a thermal conductivity of 132.7 W·m^-1·K^-1 and a thermal expansion coefficient of 18.5×10-6 K^-1, rendering it suitable for electronic packaging applications where thermal management is critical.