Based on the geological characteristics of“fragmentary，small，low，thin and deep”and the development characteristics of“three low and three high”of the small complex fault block reservoirs in Subei Basin，five development technologies are formed including the laboratory physical simulation experiment and suitability evaluation for CO2 flooding/huff and puff，the scheme design and optimization，miscible identification and development result evaluation for CO2 flooding. In addition，totally 6 supporting technologies of collection，purification，gathering and transportation，injection，oil production and recovery are formed. Under the situation of low oil price and by focusing on the two key factors of cost and benefit，the CO2 EOR method applied in low permeability reservoirs is extended to the medium-high permeability reservoirs，and also developed from single flooding/huff and puff to combination of them，which provides strong technical support for stable and increasing production and effective development in the old fields of Subei Basin.