Abstract: Based on the Pressure-State-Function-Response (PSFR) ecological security assessment model, an index system of 10 element layers and 27 index layers was constructed from four aspects,i.e. aquatic ecological pressure, aquatic ecological state, ecological function and social response. This index system was applied to quantitatively evaluate the aquatic ecological security of the Lüliang section of the Yellow River Basin by the coefficient of variation method for classification and grading. The results showed that the aquatic ecological state of the 15 sub-watersheds in the study area could be classified into three groups: insecure, general secure and secure, with no instances of extremely insecure or very secure. Among the 15 sub-watersheds, 3 sub-watersheds were at the insecure ecological status, accounting for 20.0% of the total sub-watersheds, whereas 10 sub-watersheds were at the general secure status, representing 66.7%. In contrast, only 2 sub-watersheds were grouped at the secure status, accounting for 13.3%. Furthermore, the aquatic ecological security status of the three zones delineated by distinct land use types exhibited significant spatial heterogeneity. The western hilly zone demonstrated relatively optimal conditions, yet remained constrained by ecological functional indicators such as insufficient fishery supply (annual yield <120 tons), limited tourism resource development (scenic area coverage <32%), and low compliance rate of drinking water quality (<50%). The central mountainous zone ranked second, with core constraints including high point-source pollution loads, insufficient fishery supply (annual yield <112 tons), and low proportion of aquatic recreational areas (<20%). The eastern plain zone exhibited the poorest aquatic ecological security status, characterized by multidimensional complexity in influencing factors, including high population density (290 persons/km²), intensive industrial and residential land use (industrial areas 48%, rural settlements 39%, urban areas 46%), high point source pollution load per unit area and fragile ecosystem , and fragile ecosystems exemplified by low habitat coverage (<12%). Carrying out protection and restoration work on the heterogeneous stress factors of aquatic ecological security in various areas of Lüliang section of the Yellow River Basin can comprehensively promote the effective improvement of aquatic ecological security in the basin.