Abstract: [Objective] Hydrothermal mineral deposits provide a representative example of tectonic–fluid coupled metallogenic systems, and the lateral plunge law of ore bodies or ore body clusters constitute their three-dimensional expression in geological space, yet the determination of pitching direction and pitching angle has long been one of the most difficult problems in prospecting prediction.[Methods] This study aims to address the major challenges in understanding plunge law and mechanical mechanisms, namely the difficulty of identifying ore body pitching under multiphase tectonic superposition, the lack of clarity in the control mechanisms of ore body cluster pitching, and the insufficiency of empirical studies on deep ore body pitching models. Based on Theory and Methods of Orefield Geomechanics, breakthroughs were achieved in multiphase structural recognition and the identification of control mechanisms, allowing systematic summarization of plunge law associated with compressional–shear, extensional–shear or transtensional, ductile shear zone or brittle shear belt, and composite structural controls, together with detailed analysis of their mechanical mechanisms and the proposal of practical methods for determining pitching.[Results] The results indicate that in hydrothermal deposits, ore body pitching is strictly controlled by the mechanical properties, kinematic behavior, and spatial configuration of the dominant ore-controlling structures during mineralization: the pitching direction of ore bodies or clusters is consistent with the movement of the hanging wall of the controlling fault, while the pitching angle is governed by the fault dip, the proportion of shear components, the undulatory amplitude of fault planes, and the orientation of the regional principal stresses. Ore bodies controlled by transpressional or transtensional faults exhibit more pronounced pitching than those associated with simple compressional–shear or extensional–shear structures; for single ore bodies or vein clusters, pitching direction may coincide with that of the cluster in transpressional or compressional–shear systems, or conversely oppose it in transtensional or extensional–shear systems; where ductile shear zones control mineralization, pitching is parallel to stretching lineations, while brittle shear belts produce pitching that follows extension–compression directions; in composite structural systems, the determination of pitching requires careful analysis of inherited, superimposed, or transformed tectonic elements to establish the effective mode of control. Mechanically, the pitching direction corresponds to the orientation of maximum permeability of metallogenic fluids within the ore-controlling stress field: in compressional–shear or transpressional faults, pitching is constrained by the sense of shear displacement; in transtensional faults, it is determined by the orientation of dominant fluid channels; and in ductile shear zones, it follows the X-axis of the strain ellipsoid.[Conclusion] These findings confirm that the mechanics and kinematics of ore-controlling structures are the primary factors dictating the occurrence of pitching in ore bodies and clusters, but they also highlight that the regularities differ between structural hierarchies, with the behavior of ore body clusters not entirely identical to that of single ore bodies, and that the observed patterns reflect the combined action of the metallogenic stress field, fluid dynamics, and the physical properties of host rocks. On this basis, several methods are recognized as effective for inferring the pitching of concealed ore bodies, including structural analysis of mineralizing faults, tracing zoning trends of mineralization and alteration, projection of ore column centroids, and three-dimensional spatial analysis of exploration engineering data, while the integration of structural geochemical and geophysical anomaly analyses can significantly enhance the reliability of pitching prediction in deep concealed settings, thereby opening new avenues for deep ore prospecting and achieving high efficiency in exploration.[Significance] The significance of this study lies not only in its practical applications—guiding deep and peripheral prospecting, improving mineral resource evaluation in exploration areas, optimizing the deployment of exploration projects, and enabling more accurate estimation of reserves—but also in its theoretical contributions, particularly in advancing the understanding of the metallogenic dynamics of hydrothermal deposits by linking structural mechanics, stress fields, fluid migration, and rock physical properties in a unified framework for explaining ore body pitching.