A fault diagnosis system is disclosed, including: a control unit, a first management board, a first pull-up unit, a second pull-up unit, a first pull-up switch, a second pull-up switch, and at least one central processing unit, the control unit is configured to receive physical partitioning information sent by the first management board, the first pull-up unit and the second pull-up unit are configured to pull up a fault indication signal of a fault diagnosis path to obtain a target signal, the first management board is configured to detect whether a level of the target signal is lower than a diagnosis threshold, and when the level of the target signal is lower than the diagnosis threshold, determine that a faulty central processing unit exists in the at least one central processing unit.