The invention belongs to the technical field of preparation of lithium battery negative electrode materials and relates to a method for preparing copper-aluminum-silicon alloy powder through gas atomization and application of the method, in particular to a method for preparing a copper-aluminum-silicon alloy nanometer negative electrode material of a high-performance lithium battery through gas atomization and application of the method. According to the technical scheme, the method for preparing the copper-aluminum-silicon alloy powder through gas atomization comprises the following steps thatfirst, a tundish system in an atomization device is started, and the inner diameter of a discharge spout of a tundish is phi 6-14mm; second, the tapping temperature of a molten copper-aluminum-silicon alloy is adjusted to be 1300-1700 DEG C; and third, liquid metal is poured into the tundish, the gas atomization pressure is 10-50 MPa, and gas atomization powdering is conducted, wherein the copper-aluminum-silicon alloy comprises the components of, by weight, 22-70 parts of silicon, 20-70 parts of copper, 0.5-15 parts of aluminum and 0-5 parts of impurities. The method can be widely applied tothe field of preparation of the lithium battery negative electrode materials.