The invention relates to method for performing solid-liquid separation during extraction of tobacco raw materials through a press region changeable type two-roller press and belongs to the technical field of raw material preparation and processing of reconstituted tobaccos in the cigarette industry. The method comprises the steps that A, stem liquid blend stock and debris fluid mixture which are subjected to heating extraction are pumped to the position between two parallel cylinder screens in the press region changeable type two-roller press; B, under action of pumping pressure, the materials flow onto roller surfaces of the cylinder screens in a press region evenly from the position between the two rollers of the press region changeable type two-roller press, the materials are extruded through the cylinder screens rotating in opposite directions, and extract liquor is discharged into a refined enrichment section from guide pipes in the two cylinder screens; C, the materials are conveyed into a storage tank at the rear section through a spiral conveying machine positioned at the upper portion of the press region changeable type two-roller press; D, during operation of the two-roller press, fine slag charge easily block filtering holes in the surfaces of two rollers, and the filtering holes in the two press rollers can be cleaned by high-pressure clear water subjected to pressurization. Drainability and aridity of pulp during paper manufacture with pulp are improved remarkably, and bulk and absorbability of base plates are improved remarkably.