The invention provides a creep compression experimental apparatus. The creep compression experimental apparatus comprises an installation frame connected between an upper stretching rod and a lower stretching rod of a creep test machine, wherein the installation frame comprises an upper pressure block and a lower pressure block, the upper pressure block is provided with a threaded hole A, the lower pressure is provided with a conical hole coaxial with the threaded hole A, one end of a test sample is fixed in the threaded hole A, the other end is located in the conical hole by virtue of a conical head of a conical positioning device, and when the conical head is matched with the conical hole, the threaded hole A, the conical head, the conical hole and the test sample are coaxial. The auto-positioning function is realized by virtue of a conical surface contact of the conical positioning device, so that the test sample can be well centralized in the single-axis compression process, and the instability bending possibility of the test sample can be reduced. By virtue of the reversely-arranged extension rod, the rebound displacement of a precompressed sensor measuring head in the reset process is taken as the compression creep deformation of a sample, so that the occurrence of overstroke of the sensor measuring head and damage to the displacement sensor can be effectively avoided.