Fixture is a leveler on the important part, in order to ensure the straightener smoothly, fixture design must comply with the relevant requirements. Straightening fixtures to meet conditions including spaces, targeted, precision, fast resetting and so on. 1, straightening fixtures for space requirements, because the straightener was asked to install processing more than one surface at a time, therefore also requested the fixture to meet certain requirements on the space, is to be able to meet all of each tool on the leveler may be close to surface. 2, straightening fixture should be quickly reset request, numerical control processing equipment in General, are fast replacing processing procedure processing object's transformation, in order to be able to reduce the time. 3, the straightening fixture fixed requirements, role of the straightening fixture itself is trying to fix the workpiece, workpiece processing to locate the role of workpieces in fixtures should be perfectly positioned, and base fluid of the workpiece relative to the machine the origin should be strictly determined position to meet can be implemented in the machine coordinate system workpiece and tool requirements of relative motion. 4, straightening fixture accuracy requirements