Abstract: A new twin-screw press was developed for expressing oil from high oil content seeds or special oil seeds. Its squeezing chamber adopted double-step and multiple-stage form, in which two counter-rotating parallel screws were horizontally assembled, with one directly beneath another. The worms in the feed section took the form of partially meshing that means clearance existed between each meshing flights in the longitudinal direction but they overlapped in the transverse direction; in the ram section, non-intermeshing form was taken. Design of the main parameters of the twin-screw press was introduced. Its application effect in some oil mills was investigated which showed the practical production capacity was above 74% of the rated output, the oil recovery was above 92% and the oil-in-cake rate could be as low as 3.5%. So it could reduce 30%-40% of the energy consumption compared with a single-screw press. It is suitable for both hot and cold pressing.