A bearing assembling and disassembling tool comprises a right baffle plate (1), a right support (2), a tension bolt (3), a sleeve (4), an ejecting ring (5), a lantern ring (6), a flange (7), sizing blocks (8), a jack (10), a left support (11) and a left baffle plate (12). The wheel type right support (2) with three legs is positioned at the bottom of the right end of the bearing assembling and disassembling tool, the tension bolt (3) is connected with the right end of the lantern ring (6) provided with windows (B), the right end of the tension bolt (3) is connected with the right baffle plate (1) which is provided with a groove (A) and made of a steel channel, the two rectangular sizing blocks (8) are respectively placed into the lantern ring (6) via the two windows (B), the ejecting ring (5), the sleeve (4) with a window and the jack (10) are sequentially placed at the right end of the lantern ring (6), and accordingly, the bearing assembling and disassembling tool can be used for disassembling bearings. The left support (11) is positioned at the bottom of the left end of the bearing assembling and disassembling tool, the trapezoidal left baffle plate (12) is placed on the left support (11) and connected with the left end of the elongated tension bolt (3), procedures identical to the above are carried out, and then the bearing assembling and disassembling tool can be used for assembling the bearings.