<p>Deep engineering projects, such as geothermal exploitation, geological disposal of nuclear waste, and underground energy storage, are commonly affected by temperature, in situ stress, and bedding structure, which influence surrounding-rock stability. In this study, a numerical model of bedded sandstone was developed using the Particle Flow Code in two dimensions (PFC^2D), incorporating temperature, confining pressure, and bedding angle. The strength evolution, failure mechanisms, and anisotropic responses under combined thermal and mechanical conditions were systematically analyzed. The results show that thermally induced microcracks redistribute from the bedding zones to the rock matrix as temperature increases, indicating a critical temperature threshold. Above this threshold, microcracks become more randomly distributed in the matrix, causing structural deterioration, strength loss, and changes in strength anisotropy. Increasing confining pressure suppresses tensile opening and sliding along bedding planes, thereby weakening bedding control over crack propagation and reducing strength differences among bedding angles. A strength anisotropy index, <i>λ</i>, was defined using a polar-coordinate ellipse-fitting method. <i>λ</i> first increases and then decreases with temperature, but generally decreases and stabilizes with confining pressure. Temperature and confining pressure jointly weaken bedding control on strength anisotropy. At higher temperatures, <i>λ</i> decreases and stabilizes at lower confining pressures, and bedding-controlled failure paths are also markedly weakened. This study clarifies the evolution mechanism of mechanical anisotropy in bedded sandstone under temperature, confining pressure, and bedding angle, providing mechanistic insights for stability assessment and failure analysis of bedded rock masses in deep underground engineering.</p>