A foldable computer chassis includes a first plate having multiple first fixing shafts and second fixing shafts, multiple second plates connected to two opposite edges of the first plate by the first fixing shafts, and multiple third plates movably and rotatably connected to the other two opposite edges of the first plate by the second fixing shafts. Each third plate has a fixing elastic element. When the computer chassis is folded, the second plates are rotated to lie on the first plate, and the third plates are moved and rotated to lie on the second plates. When the computer chassis is assembled, the second plates are rotated to stand on the first plate, and the third plates are moved and rotated to stand on the first plate. The fixing elastic elements on the third plates are provided for fastening the second plates with the third plates.