The invention relates to a lithium ion battery SiO composite material which comprises powder and a conductive carbon coating layer, wherein the chemical formula of the powder is SiOx; x is greater than 0.9 and less than 1.1; the volume of powder with particle diameters below 1.0mu m accounts for less than 15.0% of that of all the SiOx powder; D90/D10 is greater than 3.0 and less than 15.0; D90 is less than 25.0mu m; Dmax is less than 50.0mu m; and the median particle diameterD50 of the SiOx changes within 0.5-2.0mu m before and after carbon coating. When the composite material charges and discharges at 0-1.5V as a lithium ion battery cathode material, the reversible specific capacity is high (over 1,650mAh/g), the initial coulomb efficiency is up to a theoretical value (over 79.0%), and meanwhile the composite material has excellent cycle performance, excellent conductive performance and low volume expansion, is suitable for high-rate charge and discharge, and can be applied to the power market.