In the context of global climate warming, high temperatures have become a major stress factor limiting plant growth, development, and crop yield. Heat stress has a pronounced negative impact on the morphological, physiological, and biochemical characteristics of crops, including seed germination, photosynthetic rate, water use efficiency, pollen viability, yield, and product quality. To cope with heat stress, plants employ a series of complex molecular mechanisms to sense heat and initiate a range of defense responses to maintain cellular homeostasis and enhance heat tolerance. This review systematically elucidates the multidimensional regulatory network of plant heat tolerance, covering the latest research advancements in heat sensing, signal transduction, and gene expression regulation. It particularly focuses on several key signaling pathways in heat sensing, protein phase separation-mediated protective mechanisms, and the genetic basis of heat tolerance-related quantitative traits．Through a deep analysis of these molecular regulatory networks, this work not only expands our understanding of plant temperature response mechanisms but also provides theoretical foundations and technical approaches for molecular design to cultivate new heat-resistant crop varieties.