This paper studies supercritical fluid extraction in which we take the effects of solute concentration variation on mass transport into account. A kinetics model with variable mass transfer coefficients proposed to describe supercritical fluid extraction of grape and almond seed oil. Three distinct stages are found for extraction process, i.e., fast-extraction, slow-extraction, transition period, with a very short overflow oil in first stage. The overflow oil period is so short and the concentration variation is so slight that we think this period belongs to the fast-extraction stage. Theoretical predictions for yield distributions of supercritical fluid extraction are highly in agreement with the experimental data in literatures, which implies that the proposed model can be used to predict more mechanism for the extraction process. Moreover, the effects of involved parameters on mass transport and supercritical extraction process are shown graphically and analyzed. (C) 2017 Elsevier Ltd. All rights reserved.