<p>Double-hole granite thermal shock directional connectivity fracture tests were conducted using true triaxial pressure testing machines combined with acoustic emission (AE) and digital image correlation (DIC) methods. The effects of horizontal stress differences and thermal shock angles on crack connectivity between boreholes were investigated. Experimental results demonstrate that directional thermal shock effectively alters the stress distribution around the boreholes, ultimately inducing the formation of single-connected fractures between them. Under unconstrained conditions, directionally connected cracks form between holes within a 72 mm apart. When the hole spacing is 60 mm, directional penetration along the minimum horizontal principal stress occurs when the horizontal stress difference coefficient is less than 1. Directional penetration also occurs at thermal shock angles of 0° and 90°. Displacement and strain evolution at each measurement point along the fracture connecting the holes were identified by integrating AE ring count data with full-field deformation patterns obtained from DIC. Specifically, thermal stress drives the simultaneous initiation of thermal shock cracks at the boundaries of both boreholes. The evolution of displacement and strain progresses through three stages: gradual increase, abrupt increase, and gradual increase. The mechanism of directional fracture propagation in granite induced by thermal shock is further elucidated through the development of solid-thermal coupled damage models in COMSOL.</p>