An open external hard drive enclosure has a body, a hard drive port, at least one computer port, a power input port and a control circuit. The control circuit is electrically connected with the hard drive port, the at least one computer port and the power input port. An open chamber is formed in the body, has an inner bottom, two opposite inner long sidewalls and an inner short sidewall, and matches a size of a hard drive. The hard drive port is formed on and extends toward the open chamber. A lever is pivotally mounted on the inner short sidewall and being adjacent to the hard drive port to push out, disengage and conveniently replace a hard drive received in the open chamber.