Abstract: To investigate the effects of ultra-high pressure sterilization on the quality of low-fat walnut sauce and predict its shelf life, the optimal ultra-high pressure sterilization conditions were selected. Moreover, multivariate statistical analysis was employed to comparatively evaluate the impacts of ultra-high pressure sterilization (HPP), high temperature steam sterilization (HPST), and pasteurization (PS) on the multi-dimensional quality indices of low-fat walnut sauce, so as to screen out the appropriate sterilization method. Furthermore, based on the Arrhenius equation, shelf life prediction models under different storage conditions (4, 25 and 35 ℃) were constructed. The research results showed that HPP could better retain the original quality of low-fat walnut sauce. The low-fat walnut sauce treated by HPP (500 MPa, 4 min) had the best color, relatively high adhesiveness, moderate hardness, cohesion, chewiness, and good stability. Through the application of gas chromatography-ion mobility spectrometry (GC-IMS) combined with Orthogonal Partial Least Squares Method (OPLS-DA), 26 key volatile compounds were identified from low-fat walnut sauce. ROVA analysis revealed that 3-methylbutyral was the dominant flavor compound, primarily contributing mushroom and fruity aromas. The HPP group exhibited (E)-2-heptenal as its primary flavor component, mainly presenting grassy and cucumber-like notes. Principal component analysis demonstrated that HPP-treated low-fat walnut sauce achieved optimal overall quality (comprehensive score 1.52), serving as the most effective sterilization method. Additionally, shelf life predictions indicated 118 days under 4 ℃ storage conditions. This study provides theoretical references for quality improvement in low-fat walnut sauce production.