The additive manufacturing technology of Zr-based bulk metallic glass composites demonstrates unique advantages in the field of precision device manufacturing, owing to its capability to overcome the forming constraints of complex components imposed by traditional processing methods. However, the inevitable presence of oxygen impurities in the powder and forming atmosphere, may have an adverse impact on the microstructure and properties of the formed parts. In this study, two different processes were selected to prepare Zr₄₈Cu_46.25Al₄Ag₁Sn_0.75 alloy powders. The powders were formed by laser powder bed fusion (L-PBF) under different vacuum conditions. The influence of different powder states and oxygen contents in the L-PBF forming atmosphere on the microstructure and mechanical properties of the alloys was studied. Results indicated that the oxygen content of the alloy prepared by vacuum induction gas atomization (VIGA) was as high as 1700 ´ 10^-6. The crystallization of the VIGA powders was serious after L-PBF formation under a low vacuum atmosphere of 500 ´ 10^-6, and a large amount of brittle intermetallic compounds (AlZr₂, etc.) were precipitated. When the L-PBF formation of the VIGA powders was conducted in a high vacuum atmosphere below 100 ´ 10^-6, the crystallization behavior and precipitation of brittle intermetallic compounds were slightly suppressed. However, a brittle fracture still occurred during compression deformation. The powders prepared by the plasma rotating electrode process (PREP) had a low oxygen content (approximately 570 ´ 10^-6). When the L-PBF formation of the PREP powders was conducted in a high-vacuum atmosphere below 100 ´ 10^-6, the glass-forming ability of the alloy was high. The crystalline phase that forms in the heat-affected zone during crystallization was the B2-CuZr phase, whereas the precipitation of brittle intermetallic compounds was basically suppressed. When the energy density of the L-PBF formation was 34 J/mm³, the compressive strength of the alloy was 1973 MPa, whereas the compressive strain remained about 6%.