Based on the metallurgical reaction of Al and NiO， an in-situ Al₂O₃ aluminum alloy powder core wire for cylindrical lattice wire arc additive manufacturing is designed， followed by its thermal analysis. The in-situ Al₂O₃ aluminum alloy powder core wire with a diameter of 1.2 mm is prepared， its process performance is studied， the size and morphology of the in-situ Al₂O₃ are analyzed， and the thermal conductivity and strength of the unit rod are tested. The powder core wire is used to form a double-layer pyramid lattice structure on a cylindrical surface with a diameter of 157 mm. The results show that the maximum reaction rate temperature of the metallurgical reaction of Al and NiO is 1 038.9 ℃， which can be carried out reliably under the conditions of wire arc additive manufacturing. The aluminum alloy powder core wire with 1.5% NiO has stable arc， uniform small particle transition， stable process， and spatter rate of less than 0.74% in wire arc additive manufacturing. The surface roughness of the unit rod formed by the powder core wire is less than 10.40 μm， and a large amount of close-packed hexagonal α-Al₂O₃ is generated in situ with the size between 50-300 nm， and the interface with the aluminum matrix is well bonded. The thermal conductivity of the unit rod is 103.68 W/（m·K）， and the average tensile strength reaches 288 MPa. The diameter error of the formed cylindrical lattice unit rod is within ±0.1 mm， and the inclination error is within ±0.9°， which has high accuracy. In the heat insulation experiment， the temperature difference between the upper and lower surfaces of the lattice test piece is more than 400 ℃， which has good heat insulation performance. The compressive strength of the lattice test piece is about 65 MPa， and the compression performance is stable.