Underframe and crane

The invention relates to the technical field of cranes, and discloses an underframe and a crane. The underframe comprises a first main beam (1), a foldable second main beam (2) and a connecting assembly (3) detachably connected with the first main beam (1) and the second main beam (2). The second main beam (2) comprises a connecting part (23), and the second main beam (2) is fixedly connected withthe first main beam (1) through the connecting part (23). The second main beam (2) is foldable, so that the size of the underframe can be reduced when the underframe does not work, and transportationis facilitated. 本发明涉及起重机技术领域，公开了一种底架和起重机。所述底架包括第一主梁(1)、可折叠的第二主梁(2)以及可拆卸连接所述第一主梁(1)和所述第二主梁(2)的连接组件(3)，所述第二主梁(2)包括连接部(23)，所述第二主梁(2)通过所述连接部(23)固接所述第一主梁(1)。将第二主梁(2)设置为可折叠，从而可以在不工作的时候减小底架的体积，有利于运输。