An n-shape connected split column for underground structure comprises a prefabricated reinforced concrete column, n-shape connector, exterior packaged steel sheet, reserved connecting reinforcement and reserved high strength bolt. The subject of the prefabricated reinforced concrete column is an ordinary reinforced concrete column; the reserved connecting reinforcement is reserved on the top and bottom of the prefabricated reinforced concrete column; a high strength bolt is reserved on adjacent side faces. The n-shape connector connects with prefabricated reinforced concrete column through reserved high strength bolt; they are installed in underground structure through reserved connecting reinforcement. The exterior packaged steel sheet is pasted on the exterior of the prefabricated reinforced concrete column, and coadjacent prefabricated reinforced concrete column and connection gap between them is overall packaged to ensure the performance of split column under normal service condition. The present disclosure has clear concept and principle; it is easy to be manufactured, repaired, and installed in a key position of underground structure to decrease the damage of earthquake for an underground structure.