A test assembly adapted to test a semiconductor device is provided. The test assembly includes a main circuit board, a space transformer, an intermediary supporting element, an adhesive element, a plurality of electrical connection elements and a plurality of test probes. The space transformer is disposed on the main circuit board and has a first surface and a second surface opposite to the first surface. The first surface faces the main circuit board. The intermediary supporting element is disposed between the main circuit board and the first surface. The adhesive element is disposed between the intermediary supporting element and the first surface. The space transformer is attached to the intermediary supporting element through the adhesive element. The electrical connection elements are disposed between the main circuit board and the first surface. Each of the electrical connection elements passes through the intermediary supporting element and the adhesive element such that the space transformer is electrically connected to the main circuit board through the electrical connection elements. The test probes are disposed on the second surface and electrically connected to the space transformer.