A server chassis includes an outer case including a plurality of outer shells and an insertion space. The outer shell has an inner wall, and an outer rail structure is disposed on the inner wall of the outer shell. The outer rail structures including an outer rail-plate, an outer-rail and a set of ball slide rail. A chassis body is slidably coupled to the insertion space. The chassis body includes inner shells and an accommodating space. An inner rail structure includes an inner rail-plate, and the chassis body is capable of sliding with respect to the outer case through the inner rail-plate inserted in the outer-rail.