Seamless tube artificial reflector test block (transverse and longitudinal defect comparison sample tube) is designed according to the requirements of the standard for ultrasonic testing of seamless steel tubes used in pressure equipment of NB/T47013.15. Suitable for pressure equipment with an outer diameter of not less than 12mm carbon steel, low alloy steel, austenitic stainless steel, austenitic ferritic duplex stainless steel pipe direct contact method, immersion method of ultrasonic testing, the material of the test block should be the same as that of the testing workpiece. It is not suitable for circumferential direct contact oblique incidence detection of steel pipe with the ratio of inner to outer diameter less than 65% and circumferential immersion transverse wave oblique incidence detection of steel pipe with the ratio of inner to outer diameter less than 60%, nor is it suitable for ultrasonic detection of layered defects.