Cu-Ni-Si alloys have good conductivity of heat and electricity and are used for electrical contacts. By using this alloy as a sliding member, a material with excellent high-temperature performance can be expected. Generally, this alloy is provided as a cast or expanded material, but considering its use as a bearing material, it is also desirable to use it as a sintered material by forming (atomizing) and sintering the powder. However, it has a possibility that an oxide film, which is difficult to reduce, may be formed when the Si-containing material is powdered as an atomized alloy powder. Therefore, this study focuses on the reduction method of alloy powders containing Si and its oxide films. As candidates for reducing agents, Ti, Al, and CaF2 were selected because they easily combine with oxygen in the sintering temperature range of this alloy powder. In addition, sulfide, a solid lubricant used as a material for sliding parts, was also generated as alloy powder during atomization, and its sintering state was also observed. As a result, the sintering state changed depending on the combination of the alloy powder composition and the mixture of Ti, Al, and CaF2. The changes in the sintering state were examined by comparison of the radial crushing strength and observation of the fracture surface.