The invention relates to a telescopic valve and a switch cabinet employing the same. The telescopic valve comprises a guiding base and expansion joints movably arranged on the guiding base front and back. The expansion joints are successively nested. A front limiting structure and a back limiting structure in stopping fit with adjacent expansion joints front and back are separately arranged at thefront end and the back end of each expansion joint; a guide rail stretching front and back is arranged on the guiding base; a guiding part in guiding moving fit to the guide rail is arranged on eachexpansion joint; and the expansion joints are arranged on the guide rail front and back in a guided manner. The valve is fully guided in horizontal and vertical directions through the guide rail and the guiding parts, so that front and back guiding setting is achieved. The expansion joints are prevented from inclining, so that the expansion joints can be prevented from being stagnated and derailed, and therefore, the reliability is guaranteed favorably.