The pipelines distribute extensively in China, but pipelines cracks caused pipeline damaged frequently. Once the pipeline’s cracks are considered in the seismic condition, the performance of pipelines will face many problems. The finite element method was used to analyze the seismic responses of pipeline’s cracks. According to fracture mechanics , the time-history responses of displacement, acceleration and stress of pipeline with crack defects and seamless pipeline were obtained, and the results were also compared and analyzed. The results indicate that cracks will cause the stress concentration of the pipeline, the pipeline cracks should be considered in seismic responses of pipelines to make the pipelines in safety and economy, and more attention should be paid to the design and study of pipelines with crack defects.