Abstract: The part-through circumferential crack is a typical crack form in pipe structure, and is also one of the main causes of pipe rupture. Firstly, this paper derived the local flexibility equations of pipe with a part-through circumferential crack using linear fracture mechanics. Then, an adaptive Simpson quadrature-revisted was used to perform the numerical integration to obtain the flexibility coefficients. Finally, the dynamic testing results of the part-through circumferentially cracked pipe were used to validate the proposed resolution for local flexibility. It is found that the natural frequencies of cracked pipe by means of the proposed local flexibility and dynamic test show good agreement, which indicates that the proposed flexibility equations and the presented solutions for calculating local flexibility are reasonable.