Abstract: According to the measurement uncertainty requirements of the key parameters of the declared tolerances of the products in the industrial standards of respiratory therapy equipment such as GB 9706.212—2020 Medical electrical equipment—Part 2-12: Particular requirements for basic safety and essential performance of critical care ventilators, YY 9706.270—2021 Medical electrical equipment—Part 2-70: Particular requirements for basic safety and essential performance of sleep apnoea breathing therapy equipment, and YY 9706.274—2022 Medical electrical equipment—Part 2-74: Particular requirements for basic safety and essential performance of respiratory humidifying equipment, this study introduces and analyzes the evaluation process of the uncertainty of the key parameters of critical care respiratory, sleep apnoea breathing therapy equipment, and humidifier, and it gives the sources and results of measurement uncertainty. It is expected that it can provide suggestions for the medical device testing laboratory to meet the uncertainty requirements of quality management and provide references for relevant manufacturers to meet the requirements of industrial standards.