The invention belongs to the technical field of oil exploitation, and relates to a refracturing modification process for a low-permeability and low-yield gas well, in particular to a CO2 refracturing process technology for a low-permeability gas well. The CO2 refracturing process technology is used for performing secondary fracturing construction for an implemented well, comprises analysis and optimization before fracturing and fracturing construction, and is characterized in that the analysis and optimization before fracturing comprises fracturing failure analysis, fracturing material optimization and construction parameter optimization, and the specific process technology is implemented according to steps of fracturing failure analysis, fracturing material optimization, construction parameter optimization and refracturing construction. According to the CO2 refracturing process technology for the low-permeability gas well, a CO2 foam fracturing technology and low-damage cleaning fracturing liquid are used for performing a modification test for a low-yield gas well by analyzing a reservoir, the flowback rate of the fracturing liquid and the yield of the low-yield gas well are increased effectively, and damage to the reservoir is effectively reduced.