In the engineering of aerospace and nuclear power engineering, the safety and reliability of small pipe（Outer diameter less than 2-inch, about 50 mm） has become one of the main factors restricting the safe operation. However, in the existing design codes, there is a lack of detailed technical requirements and evaluation criteria for small pipeline. In this paper, based on the experimental and FEA analysis, the fatigue and final fracture of pipeline components are discussed. The results show that the results of the fatigue crack propagation by experimental and FEA method are same, and they account about 3 % of the fatigue life in the study case. The critical failure mode is the plastic collapse, so it is to increase the critical crack size by increasing the tensile strength.