CO₂ flooding technology is an effective technical means to enhance the recovery of low permeability reservoirs. After CO₂ comes into contact with crude oil，the asphaltene in the system is deposited in a solid form， which causes a certain blockage to the reservoir，but the dissolution improves the flow capacity of the reservoir as a whole at the same time. The damage of CO₂ flooding to low permeability reservoirs under different injection methods is different. The organic scale plugging mechanism，reservoir wettability，and CO₂ -water solution corrosion evaluation experiments were carried out after continuous CO2 injection and CO₂ -water alternating injection. The variation characteristics of relative permeability curve parameters were evaluated，and the damage of different injection methods of CO₂ flooding to low permeability reservoirs was quantitatively characterized. The results show that the organic scale produced by CO₂ flooding would block the pore throat of the rock，but on the whole，the dissolution caused by the reaction of CO₂ and chlorite is stronger， which makes the recovery of the low permeability reservoirs effectively enhanced. More‐over， the organic scale blockage caused by CO₂ -water alternating injection is weaker than that caused by continuous CO₂ injection，and the dissolution effect is better. The permeability loss rate is lower. It could achieve a better oil displacement effect in pores with a radius of more than 0.2 μm and increase the pore space and flow channel of the rock so that the recovery of low permeability reservoir could be effectively improved.