The JF 1126-2004 standard applies to the calibrating work of Ultrasonic Thickness Gauge with resolutions of 0.1mm and 0.01mm. The calibrate specification refers to a number of related standards, including measurement terminology, measurement uncertainty assessment and representation, and ultrasonic inspection terminology. Ultrasonic Thickness Gauge is mainly used for the measurement of the thickness of metals and Non-metallic materials. The working principle is based on the measurement of the time when the probe emits and receives ultrasonic waves. Calibrate covers multiple measurement characteristics such as Repeatability, Error of indication, and fine-tuning range of thickness calibrate to ensure the accuracy and Stability of measurement results. Calibrating conditions require that the indoor temperature and relative humidity meet the regulations, and calibrate using standard thickness blocks and calibrated thickness blocks that meet the technical requirements. In addition, the calibrating results should be confirmed by the calibrating certificate. It is recommended to re-calibrate once a year to ensure the Reliability and accuracy of the measurement equipment.