This study investigated the effects of ball-milling treatment on the characteristics of gorgon euryale starch (GES) and quinoa protein (QP), and developed a new strategy by compounding ball-milled GES with QP to study the mechanism of its action on the stability of Pickering emulsions. Through SEM and FTIR analyses, it was found that ball-milling treatment damaged the compound granular structure of GES, reduced the particle size of QP, and caused aggregation. However, the chemical structures of both substances did not change significantly. The Pickering emulsions prepared with the ball-milled GES/QP complex exhibited more significant thickening properties. Ball milling reduced the droplet size of the emulsions (D50 decreased from 6.73 ± 0.12 to 2.85 ± 0.91 μm) and made the distribution more uniform, though an excessive protein ratio led to droplet aggregation and a decrease in the emulsification index. Using the emerging observation method of DIC, it was confirmed that the emulsions prepared with GES/QP (8/2, g/g) and GES/QP (7/3, g/g) showed almost no change in backscattering light intensity and still had good storage stability after 20 days. This study provides a theoretical basis for the development of more stable and clean emulsifiers.