Embodiments of the present disclosure relate to a guiderail for a cabinet, a chassis and a cabinet. Specifically, the present disclosure discloses a guiderail (1) used in a cabinet (100) and the corresponding chassis (2) and the cabinet (100). The guiderail (1) is mounted in the cabinet (100) and used to fix the chassis (2) which can accommodate storage processing units (3) with different dimensions. According to the present disclosure, the guiderail (1) comprises a main body part (10) and an extended part (30), wherein the main body part (10) is used to support the chassis (2) when it is inserted into the cabinet (100) along the guiderail (1); and the extended part (20) is used to fix the storage processing unit (3) extending from the chassis (2) so that storage processing units (3) of different dimensions can share the chassis (2) with the same specification.