High dietary fat food such as mayonnaise (70-80% oil content) can induce obesity and cardiovascular diseases, thus reducing their oil content is required. However, the development of low-fat mayonnaise is still a big challenge since reducing oil content will increase the fluidity, induce phase separation and decrease the stability of mayonnaise. Herein, we provide a novel strategy for developing yolk-casein-based low-fat mayonnaise (30% oil content) with a similar texture to commercial high-fat mayonnaise through post-acidification. Unexpectedly, compared with pre-acid-treated low-fat mayonnaise, the G' and viscosity of the post-acid-treated low-fat mayonnaise were significantly improved by 77.80% and 90.18%, respectively. The semisolid properties required for low-fat mayonnaise were realized by forming a dense yolk-casein self-assembly network structure. This study provides a novel perspective for constructing edible soft-solid products with low fat intake.