Abstract: The effects of doped Al nanoparticles（0-0.5wt%） on the interfacial structure, wettability and shear strength of Sn-based solder joints used for chip stacking interconnect in 3D packaging technology were investigated. The results show that the doped Al nanoparticles can significantly inhibit the growth of intermetallic compounds at the interface layer of Sn-based solder joints. When the doping amount of Al particles is 0.3wt%, the thickness of the interfacial layer decreases from the initial of 3.00 μm to 2.28 μm. However, when the doping amount of Al nanoparticles exceeds 0.3wt%, the thickness of the interface layer of the composite solder joint increases. In addition, with the doping of trace Al particles, the melting point of the solder does not change significantly, and the wetting angle of the Sn-based solder decreases. When the doping amount of Al nanoparticles is 0.3wt%, the wetting angle of Sn-based solder decreases from the initial without doping of 16.8° to 13.4°, a decrease of 20.2%. For Sn-0.3Al composite solder joint, the shear strength reaches the maximum value of 16.9 MPa, an increase of 24.3%. However, the wettability and shear strength of the composite solder joints decrease gradually with the increase of Al nanoparticle doping amount.