Abstract: Since there is no systematic and scientific evaluation and prediction of the efficiency of hydrotechnical prevention projects along oil and gas pipelines, the limited pipeline maintenance resources can not be fully and efficiently optimized, it is necessary to carry out follow-up evaluation based on efficiency evaluation. Based on efficiency characteristics and classification of hydrotechnical prevention projects, efficiency evaluation of 347 hydrotechnical prevention projects in 15 pipelines, such as WuLan Pipeline, the 2nd West-to-East Gas Pipeline has been conducted based on "input-output" model by the established "single input-double output" evaluation method. Risk mitigation index and engineering usability index in the evaluation can directly reflect the protective effect, quality and maintainability of hydrotechnical prevention projects. The efficiency evaluation results are valuable data for optimizing investment decision, improving project efficiency, and can provide a guidance to the maintenance and construction of hydrotechnical prevention projects for operating companies.