With rapid industrial development, selective laser melting (SLM) has emerged as a critical manufacturing technique for forming complex components made of high-strength, high-thermal-conductivity copper alloys in the aerospace, aviation, and defense sectors. To address the processing challenge of achieving high-density SLM for highly thermally conductive/highly light-reflective Cu-Ag-Zr alloys, orthogonal experiments were employed to optimize the process parameters and combine remelting techniques to realize high-density alloy formation. The effects of the laser power, scanning speed, and hatch spacing on the densification behavior, microstructure, hardness, and thermal conductivity of the SLM-processed Cu-Ag-Zr powder were systematically investigated. Under a specific powder size range (20~53 μm), with remelting applied, and within a laser power range of 420~500 W and a volumetric energy density of approximately 300 J/mm3,sufficient laser energy input significantly improves the distribution of melt pools and effectively reduces the lack of fusion pores. Moreover, the characteristic rapid solidification of SLM promotes a uniform distribution of alloying elements, resulting in a relatively dense bulk alloy with a relative density of 99.87%. A pronounced <001>//BD texture is observed on the printed surface. The optimized Cu-Ag-Zr alloy has a microhardness of 122.6 HV0.5 and a thermal conductivity of 252 W/(m·K).