The invention provides a method for judging CO2-flooding inter-well connectivity through component contents. The method for judging CO2-flooding inter-well connectivity through component contents includes the steps that 1, before CO2 is injected and during steam injection, natural gas samples are collected, and the component contents of the samples are detected; 2, by utilizing measured data, a curve showing change of the CO2 component concentration in an observation well along with injection time is made; and 3, the changing rule of the curve is observed, and the CO2 component concentration in each observation well is compared with the initial CO2 component concentration, so that CO2-flooding inter-well connectivity is judged. The method for judging CO2-flooding inter-well connectivity through component contents is carried out in the state that the wells are not closed, no damage is caused to normal production and stratums, inter-well connectivity can be accurately and effectively judged, and the method is low in cost, does not affect normal crude oil production, and is suitable for conventional oil reservoirs and low and ultra-low permeability oil reservoirs.