Environmental factors have an important influence on performance index of hydrogen maser. It must be controlled seriously while measuring or using the hydrogen maser. This article researches from the construction of hydrogen maser, analyzes the factors which affects the frequency stability of hydrogen maser, and focuses on the analysis and experiment about the influence of environment temperature. The experiment shows that the environment temperature has a little influence on short-term frequency stability, but it will affect the index of long-term stability seriously.