In order to reveal the influencing mechanism of asphaltene precipitation on oil recovery during CO2 flooding in the tight sandstone reservoirs，three kinds of crude oil samples with different asphaltene contents and low-permeability artificial cores（epoxy resin cemented quartz sand）were selected for flooding tests. The flooding tests were carried out by stimulating actual formation temperature and pressure. The effect of asphaltene precipitation on the oil recovery of different scales of pore throat was analyzed by nuclear magnetic resonance（NMR）technique. The results show that the amount of asphaltene precipitation is proportionate to asphaltene contents of the crude oil during flooding. It also increases with the increasing CO2 injection volume. At the same time，the oil recovery will be affected by asphaltene，which decreases with the increasing precipitation amount. The results of NMR test show that the asphaltene precipitation had little effect on the oil recovery of the larger pore-throats（2.0-200.0 ms）. However，the asphaltene precipitation produced a certain degree of clogging in the smaller pore-throats（0.1-2.0 ms），resulting in the remaining oil being difficult to be recovered and ultimately affecting the overall recovery.