A liftable table has a table frame, a fixing board, a lifting device, and a table board. The table frame has a main frame and a holding seat. The holding seat is deposited on the main frame. The fixing board is mounted on the main frame. The lifting device is deposited on the holding seat and has a driving set and at least one crossing set. The crossing set is extended from or folded in the receiving space of the holding seat, and is connected to and driven by the driving set. The table board is deposited on the crossing set to move upwardly or downwardly. A user views and operates a computer put on the table board with a sitting or a standing posture, and this prevents the user from using the computer with the sitting posture for a long time and avoids damages to the user's health.