Abstract: Heat treatment has found extensive applications in the research realm of enhancing the permeability of coal reservoirs. In light of the issues of an unclear evolution mechanism of the fracture network in coal under the induction of hot nitrogen and an insufficient quantification of the response disparities in different maceral regions, this study independently constructed a high-temperature nitrogen reaction system. By integrating X-ray computed tomography (CT) and Node-Branch (NB) topological graph theory methods, it systematically uncovered the dynamic evolution law of the microscopic fracture network in coal during the heat treatment process spanning from 60 to 180 ℃. The experiment targeted the semi-bright coal in the Baode block of the Ordos Basin, with a focus on exploring the collaborative control mechanism of temperature and coal lithology components on the fracture expansion mode, spatial orientation, and connectivity. The findings indicate that: the hot nitrogen treatment significantly modifies the fracture structure through fracture expansion, extension, generation, bifurcation, merger, and networking behaviors, ultimately achieving the interconnection of fracture networks in different component regions, and the fracture evolution exhibits notable maceral dependence. The fractures in the vitrinite region (V_A region) demonstrate a more intense response, with the topological connectivity C_L increasing by 38.6%, whereas the C_L in the inertinite region (I_A region) only experiences a 9.2% increase. Temperature and components jointly play a dominant role in governing the change of fracture orientation. In the low-temperature regime (< 90 ℃), the newly formed fractures are predominantly low-angle fractures (< 30°), whereas in the high-temperature regime (> 120 ℃), high-angle fractures (> 60°) become more prevalent. Moreover, there exist notable disparities in the fracture angle distribution between the V_A and I_A regions. Three-dimensional reconstruction reveals that the volumetric fracture porosity increases by 143.08% at 180 ℃. However, there is a physical constraint on the widening of fracture aperture, with a peak value of 166.65 μm, suggesting that the thermal widening effect exhibits a weakening tendency. Based on the characteristics of fracture response intensity, node type, angle distribution, and connectivity alterations, the thermally induced fractures manifest distinct stages: the initial activation and expansion stage (60−90 ℃), the intense cross-linking and activity stage (90−150 ℃), and the networking and local spalling stage (150−180 ℃). This study furnishes a theoretical foundation for the targeted temperature control and the prevention and control of damage risks associated with the thermal recovery technology of coalbed methane reservoirs.