Seeds are another product in addition to leaves (raw materials for teas) of tea (Camellia sinensis L.) plant. The great increase of tea consumption in recent years raises the challenge of finding commercial applications for tea seeds. In the present study, supercritical carbon dioxide (SC-CO(2)) extraction edible oil from tea seed was carried out, response surface methodology (RSM) was used to optimize processing parameters including time (20-90 min), temperature (35-45 degrees C) and pressure (50-90 MPa). The fatty acid composition and antioxidant activity of the extracted oil was also investigated. The highest yield of oil (29.2 +/- 0.6%) was obtained under optimal SC-CO(2) extraction conditions (45 degrees C, 89.7 min and 32 MPa, respectively), which was significantly higher (p < 0.05) than that (25.3 +/- 1.0%) given by Soxhlet extraction. Meanwhile, tea seed oil extracted by SC-CO(2) contained approximately 80% unsaturated fatty acids and showed a much stronger scavenging ability on the DPPH radical than that extracted by Soxhlet. SC-CO(2) is a promising alternative for efficient extraction of edible oil from tea seed. Moreover, tea seed oil extracted by SC-CO(2) is highly edible and has good antioxidant activity, and therefore may play a potential role as a health-promoting food resource in human diets.