Self-adaptive type extensometer with multiple deformation modes

The invention discloses a self-adaptive type extensometer with multiple deformation modes. The self-adaptive type extensometer comprises two positioning bolts, two both-way connecting nuts, two universal hinge assemblies, two connecting bolts, two connecting sleeves, a first retractable steel pipe, a second retractable steel pipe and an extensometer. With adoption of reasonably designed positioning bolts, one-dimensional samples with smaller cross sections can be fixed in a bound manner; samples with larger cross sections are fixed in a pre-buried manner, and the application range of the self-adaptive type extensometer with multiple deformation modes is expanded; the universal hinge assemblies have good rotating performance in all directions, so that various deforming conditions of tested samples can be adapted to, axes of the first retractable steel pipe and the second retractable steel pipe are located on the same straight line without dislocation and the first retractable steel pipe and the second retracta