The invention provides a modified graphite particle system for strengthening a polymer/binary/ternary composite oil displacement system. The modified graphite particle system comprises the following components: 1-5 parts by mass fraction dispersed graphite particles, 0.2-0.6 parts by mass fraction dispersant, 0.1-0.5 parts by mass fraction wettability modifier, and deionized water that accounts for the remaining content, based on 100 parts by total mass fraction of the components. In addition, the present invention also provides a preparation and a use of the modified graphite particle system for strengthening the polymer/binary/ternary composite oil displacement system. The modified graphite particle system for strengthening the polymer/binary/ternary composite oil displacement system can be used to improve mobility regulation ability and oil displacement efficiency in an injection stage, enhance injection pressure in a follow-up water displacement stage, and increase the oil displacement effect of the composite oil displacement system to the greatest extent.