Abstract: Welded pressure pipes were widely used in the fields of energy source,transportation and so on.It is very important to ensure the safety and reliability of pressure pipes,that in the hydroelectric power station is the focus,because once it is destroyed,the heavy loss zoill be suffered.Based on the experiments the fracture characteristics of welding joint in new pressure pipes used for hydroelectric power station were discussed at room temperature in this paper.The ANSYS codes have been employed to simulate the conditions of pipe loading and to analyze the piping stress distributions.According to ASME Piping Flaw Evaluation, the stability and safety in ferritic steel piping have been calculated.The assessment results indicated that the safety could meet the requirement of working conditions.