Abstract: In this study, the temperature sensitive analysis model of the high temperature steam electrolysis (HTSE) system was established through electrochemical method. Temperature sensitivity of the HTSE system was analyzed using this model. The concept of temperature sensitive coefficient was put forward originally. Qualitative researches show the temperature sensitive coefficient increase with operation temperatures increasing under various electrical efficiency (η_el), electrolysis efficiency (η_es), and thermal efficiency (η_th), which indicate the overall system efficiency of the HTSE system increases with operation temperatures increasing. And the temperature sensitive coefficient increase with η_el and η_th increasing, while η_es has little effect on the temperature sensitive coefficient. Quantitative researches show the temperature sensitive coefficient is 1. 4 with the operation temperatures in the range of 750-950 ℃, which indicates the overall system efficiency increases about 10. 5% and 12%, when the operation temperatures of the HTSE system are 800 and 900 ℃, respectively. Then the overall system efficiency of the actual HTGR coupled with HTSE system is as high as 55. 8% and 56. 5%, respectively, which is about two times higher than that of the conventional alkaline water electrolysis.