The invention discloses a rubber tube fixing device. The rubber tube fixing device comprises a rack. Two fixing mechanisms are symmetrically arranged on the rack. Each fixing mechanism comprises two fixing blocks which are arranged symmetrically, wherein lead screws are arranged on the fixing blocks in a penetrating mode correspondingly, an arc-shaped clamping block is arranged at one end of each lead screw, the other end of each lead screw is fixed through a nut, and the two arc-shaped clamping blocks are arranged oppositely. A convex plate is arranged on the outer side of one fixing block on the rack. The convex plate is concave downwards, so that a rectangular groove is formed. A plurality of sets of fixing holes are symmetrically formed in the two side walls of the rectangular groove. Elastic structures are arranged at the bottoms of the fixing holes. A limiting plate is fixed in the fixing holes through the matching of lugs arranged at the bottom of the limiting plate and the elastic structures. A clamping groove matched with a rubber tube is formed in the limiting plate. According to the rubber tube fixing device, the fixing blocks and the clamping blocks matched with the fixing blocks are arranged, rubber tubes of different dimensions can be clamped by adjusting the positions of the lead screws, and thus the problem that an existing clamping device can only be used for clamping rubber tubes of the same dimension is solved.