In order to evaluate the water security status and identify its obstacle factors in Northwest China, this study divides water security into three parts: water resource security, water environment security and water ecological security, constructs a water security evaluation index system and model, uses the set pair analysis method to evaluate the water security in Northwest China from 2015 to 2020, and establishes an obstacle degree model to diagnose the main obstacle factors affecting water security in different regions.Water security levels have generally increased in the Northwest regions, but overall levels remain low.The water security pattern in the northwest region has significant geographical characteristics, with the central region having the best water security, followed by the eastern region, and the western region being relatively poor.Water environment security is the weakest link in water security in Northwest China, which needs to be paid great attention to and effective measures should be taken to deal with it.The analysis of the obstacle factors in each region shows that the factors affecting regional water security are not the same.Although the water environment security in the eastern and central regions is similarly low, the eastern region is mainly due to the rapid development of cities and the discharge of high industrial wastewater and domestic sewage, while the central region is due to insufficient urban sewage treatment capacity and lack of urban water system infrastructure. In contrast, the western region is mainly constrained by water efficiency issues.