A rotatable fixture for use in a vibration or seismic test is capable of shortening the time for dismantling the fixture. The rotatable fixture of the present invention is aimed to obviate the non-universalness of the conventional fixture and remove the drawbacks that the conventional fixture has to be dismantled before rotating to a certain angle for test. The rotatable fixture of the present invention includes a base, a rotating disc, a fastening frame, and fixing plates. The rotatable fixture has a basic natural frequency which is distant from the test frequency band. Meanwhile, the drawbacks that the fixture has to be dismantled during the test process is eliminated by the special connection between the base and the rotating disc. Moreover, due to the versatile design of the fastening frame, the rotatable fixture can allow a variety of devices under test to be secured thereto to attain universalness.