The invention discloses a pipe column structure for the CO2 flooding gas injection process. The pipe column structure comprises a guiding shoe, a check valve, a setting ball seat, a Y445 packer, an inserting pipe, a reverse circulation valve and an oil pipe. The guiding shoe is connected with the check valve; the upper end of the check valve is connected with the setting ball seat; the upper end of the setting ball seat is connected with the Y445 packer; the Y445 packer is connected with the inserting pipe; and the upper end of the inserting pipe is connected with the reverse circulation valveand the oil pipe in sequence. During working, the parts are connected in sequence, a pipe column is put downwards, an annulus is filled with a conventional oil-based annulus protection fluid in a reverse circulation mode, a quick-dissolving soluble ball is put, pressure injection for setting is conducted, and thus gas can be injected normally; when the pipe column is taken out, through the checkvalve, the oil pipe is directly emptied so that pressure can be released, the pipe column is lifted up, the inserting pipe is pulled out, and thus a pipe string can be taken out; if pressure relief ofthe oil pipe fails, a well killing fluid is injected in a reverse circulation mode for well killing, then the pipe column is lifted up, and thus the pipe string can be taken out; after pipe string checking work, the parts are connected in sequence, the pipe column is put downwards, the inserting pipe is inserted into the packer, and thus sealing well-completion can be conducted.