To risk of damage to existing submarine pipelines and cables during the construction of new projects in marine engineering,this paper takes the construction of approach bridge crossing submarine pipelines as an example,and systematically elaborates and analyzes the key construction ideas and technical applications of crossing pipeline engineering around the protection of submarine pipelines during on-site construction.The conclusion indicates that underwater exploration of submarine pipelines is still the most direct and effective way to determine the location of pipelines.Before exploration,sufficient analysis for pipeline information should be conducted,and safe techniques to pipeline surface dredging should be adopted.After determining the location of the pipeline,accurate and clear pipeline markings and vessel traffic signs should be set up at sea before construction to achieve visualization of the underwater pipeline and maritime traffic.Considering account various working conditions,Pre-fixed anchors can greatly reduce the risk of ship anchoring,and multi-level monitoring during construction is also an important measure to ensure pipeline safety.