The invention relates to an adjustable sheet part-grabbing manipulator, which comprises a vacuum suction type manipulator mechanism of a bed plate with four mechanical arms, and each mechanical arm is provided with a suction foot; the improvement is that a pair of sheet part support mechanisms and four suction foot distance adjustment mechanisms are added; the pair of sheet part support mechanisms are symmetrically arranged on the bed plate at one side of a connecting base, and respectively neighbor the mechanical arms; as a sheet part is sucked by the four suction feet, under the drive of hydraulic cylinders, a pair of support arms are closed to grab the sheet part or opened to put down the sheet part; each suction foot distance adjustment mechanism comprises a distance adjustment hydraulic cylinder, a distance adjustment guide way and one suction foot; the fixed ends of the suction feet are slidably fitted in the distance adjustment guide ways, and under the drive of the distance adjustment hydraulic cylinders, the suction feet move along the distance adjustment guide ways to adjust positions. The adjustable sheet part-grabbing manipulator can grab different sizes of sheet parts; the cooperation between the sheet part support mechanisms and the vacuum suction type manipulator mechanism ensures that the sheet part can be more safely and reliably grabbed and transferred.