The security situation of city gas gate stations decides whether the city gas system in the whole city can get in normal safety operation，so the faulty tree and fuzzy theory method were suggested to analysis safety situation for city gas gate stations. By analysis on the risk factor of city gas gate stations，the faulty tree for the main system of city gas gate stations was established，twenty-eight elementary events causing the main system fault of city gas gate stations were obtained，and safety assessment index system was established. The quantitative analysis on the safety situation of the city gas gate stations was made by fuzzy comprehensive assessment theory and the score of index was determined by expert assessment, and assessment index weight was established by analytic hierarchy process method. The safety degree of the city gas gate stations was obtained by fuzzy theory, and the corresponding key routine safe working was obtained. All these were used in the safety assessment of the city gas gate stations in Changzhou, and the city gas gate stations safety degree is Ⅱ.The example proves that the method used in safety assessment result of the city gas gate stations is effective and reliable，which provide useful reference for safety management on the city gas gate stations.

Spherical tank is more important equipment for stored or packing of gases, liquids and other media of the petrochemical. Its reliability is an important index for security. The concept of reliability analysis was explained. By using finite element software, the reliability of spherical tank and parameter sensitivity was analyzed and evaluated. Parameters' reliability and sensitivity can visually reflects influence of normal distribution design parameters on the reliability and provide scientific reference for reliability design of spherical strength.