Abstract: To ensure reliability and safety of the drilling coring operation,both tensile property and torsional property of the coring tool thread are studied by means of three methods,i.e.,theoretical calculation,finite element simulation and full-scale strength evaluation test.During the test,strain gauges are attached near the inner and outer threads of the coring tool,and the test-resulting strain is compared with the FE-calculated strain.The test and calculation results show that the full-scale strength evaluation test result is in good agreement with the FE calculation result,which is capable of providing technical and theoretic supports to the research on the strength property of threads of the coring tool with other sizes and types and for hi-temperature coring service.