Abstract: When mechanical pipe clamp is used to temporarily plug the leak, the operation with shutdown is time-consuming and has great impacts on downstream pipeline, while the operation without shutdown is risky and costly. In this regard, the isolated sleeve remediation technology of subsea pipeline is proposed. It is designed in strict compliance with domestic and international standards and all stress concentration points are checked using the finite element method. Through theoretical research and simulation experiment, the isolated sleeve is proved as a safe and reliable remediation technology for in-service pipeline. The technology is successfully applied to local leak of Panyu 30-1 subsea pipeline. During the operation, original pipe clamp is retained and the pipeline is shutdown. The technology helps to improve the on-line maintenance of domestic pipelines.