Using sodium bisulfite aqueous solution as extractant, the reactive extraction experiments for a heptaldehyde−undecane mixture were carried out. The results show that when the molar ratio between sodium bisulfite and heptaldehyde, the stirring speed, the volume fraction of aqueous phase or the temperature increase, the reactive extraction rate increases. In contrast, larger molar ratio between sodium bisulfite and heptaldehyde, smaller volume fraction of aqueous phase or lower temperature leads to higher equilibrium conversion of heptaldehyde. According to the mass transfer coefficients of the reactive extraction system and the rate constants obtained from the study of intrinsic kinetics, the Ha numbers were estimated. The results show that under the conditions in this paper, 0.3 < Ha < 3, the reactive extraction process was mainly a mixing control process. Since heptaldehyde is soluble in water while sodium bisulfite is not soluble in undecane, the reaction occurs within the film and the main body of the aqueous phase. For the reactive extraction of 1.0 wt % heptaldehyde in undecane using aqueous sodium bisulfite as the extractant, three methods of performing three-stage reactive extraction were investigated. The results showed that equilibrium extraction is highly necessary to ensure the extraction efficiency. Cross-current equilibrium extraction is suitable for situations where high product purity is required; for situations where the separation requirements are not too high, counter-current equilibrium extraction should be preferred.