The invention discloses an adjustable fixture suitable for spaceflight precise parts of multiple shapes and sizes. The adjustable fixture consists of middle plates, side wing plates, control plates, lead screws, connecting shafts and support clamps. Two middle plates are used as main fixture pieces; and the lead screws and the control plates on the back side are used for controlling the side wing plates on two sides of the middle plates to change the clamping force to products. When the sizes of the products are smaller, the fixture on one side is used; and when the sizes of the products are bigger, the fixtures on two sides can be synchronously used for clamping. The adjustable fixture eliminates the defect that a general fixture cannot be suitable for clamping the products of any sizes and any shapes; and the states of the fixture can be changed according to the sizes and the shapes of the products, so that the application range of the fixture is widened, and the working efficiency in industrial production is improved.