Abstract: Ultrasonic method, an effective way to measure on-line stress on oil and gas pipelines in nondestructive testing field, can take an accurate measurement of stress on the dangerous point. It has a significant influence on the safety of operating of deformed pipe sections. The accuracy of ultrasonic method, a kind of sensitivity testing techniques, is mainly affected by ambient temperature and the curvature of pipelines. Based on acoustic elastic theory, we first analyze the influence of temperature on LCR time-of-flight t₀ in free stress specimens and propose modified formulas. Then, the influence of the curved surface coupling state on the measurement is analyzed and the method of stress coefficient correction based on radius of curvature of pipeline is proposed. The theoretic correction model has been verified by temperature and pipe pressing varying experiments on an independently developed experimental platform of LCR waves stress measurement. The results show that the theoretically deduced formula of the relationships between the time of flight of LCR waves and temperature are basically consistent with the experimental fitting formula of that in stress-free specimens. In terms of result and distribution trend of measured circumferential stress value, ultrasonic method is consistent with strain method after stress coefficient is corrected based on radius of curvature of pipes. The findings in this paper effectively improve the accuracy and reliability of ultrasonic method of measuring pipe stress.