Load impact, such as the rockfall, may bring significant threats to the integrity management of pipeline. This study is intended to evaluate the reliability of buried pipeline under rockfall impact, and so as to reduce the possible failure and unnecessary downtime. Firstly, the dynamic response of the buried pipeline under load is analyzed by Euler Bernoulli foundation beam. After that, the process of rockfall impact on buried corroded pipeline is simulated with nonlinear finite element method. Furthermore, the influence of rockfall’s parameters (including rockfall mass, impact velocity, impact position, etc.) on the pipeline’s equivalent stress is quantitatively analyzed. Eventually, a time-varying reliability model is established to calculate the failure probability. The results indicate that the mass and velocity of the rockfall have obvious influence on the pipeline’s failure probability, and the change of impact’s position has small influence. The proposed method can provide a theoretical reference for the design and maintenance of buried pipeline.