Abstract: To investigate the regulatory mechanism of pH on the heat-induced gelation behavior of the potato protease hydrolysate (PPH) and pectin (PEC) composite system, this study prepared PPH-PEC composite gels under varying pH conditions. The physicochemical properties of the gel were evaluated through macroscopic gelation observations, water-holding capacity (WHC) measurements, and protein solubility analysis. Additionally, the mechanisms underlying its microstructural formation were elucidated using confocal laser scanning microscopy (CLSM) and various spectroscopic techniques (FTIR, UV, and fluorescence). This study systematically assessed the gel’s physicochemical properties and elucidated the mechanisms governing its microstructural formation. This approach systematically assessed the gels and elucidated their microstructural formation mechanisms. Results indicate that the gelation behavior of this composite system exhibits significant pH dependence. Structurally intact gel networks with excellent water-holding capacity form only within a specific pH range, while extreme acidic or alkaline conditions prevent effective gelation. Spectroscopic and microscopic analyses revealed that an optimal pH environment enhances the conformational unfolding of the PPH peptide segment, thereby optimizing electrostatic attraction, hydrogen bonding, and hydrophobic interactions between PPH and PEC. This promotes the formation of a dense, uniform three-dimensional network. Conversely, unfavorable pH conditions lead to dominant intermolecular repulsion or conformational folding, hindering network assembly. This study elucidates the key mechanism by which pH influences the microstructure and macroscopic properties of PPH-PEC composite gels by regulating the balance of intermolecular forces, thereby providing important theoretical foundations and technical support for the development of PPH gel-based foods and the high-value utilization of potato protein.