The invention provides a fixture for wire-cut electrical discharge machining of workpieces with the different lengths and different shapes and particularly relates to the field of fixtures. The fixture comprises a base and a pressing plate arranged on the upper portion of the base; a sliding groove matched with a T-shaped block on the base is formed in the pressing plate and can be used for adjusting the height of a workpiece clamping groove; four positioning screws on the pressing plate are used for guaranteeing positioning of the workpiece, and two compressing bolts on the pressing plate areused for compressing the workpiece so as to facilitate mounting and demounting of the to-be-machined workpiece; two eye bolts are additionally arranged on the pressing plate; and in addition, aimingat the detect that numerous fixtures fail in precise fine adjustment of the levelness, according to the fixture, fine adjustment block storing grooves are excavated in the upper side of the front endface of the pressing plate, and the workpiece clamping precision can be guaranteed through bolts on fine adjustment blocks. The fixture has the beneficial effects that the fixture can mount, positionand clamp the workpiece on a wire-cut machine tool flexibly and rapidly even if the workpiece is long or is in an irregular shape, and the working efficiency is improved greatly.