The embodiment of the invention provides a clock switching method and device, a server and a clock system, and the method comprises the steps: receiving a standby clock signal through a standby clocksignal input port of a switching circuit when detecting that a main clock signal is abnormal; reconstructing the phase of the standby clock signal, generating a reconstructed clock signal, and the phase of the reconstructed clock signal being consistent with the phase of the main clock signal before abnormality; and compensating the phase of the reconstructed clock signal according to the standbyclock signal and a preset phase adjustment speed, generating a compensated clock signal, outputting the compensated clock signal through a clock signal output port of the switching circuit, and the compensated clock signal being consistent with the standby clock signal in phase. According to the clock switching method provided by the embodiment of the invention, the phases of the clock signals ofthe TSCs provided for the processors can be ensured to be consistent, and the normal work of an operating system of a server is ensured.