To accurately predict the propagation behavior of supercritical carbon dioxide (SC-CO2) fracturing fractures in shale reservoirs with natural fractures, this study established a thermal-hydraulic-mechanical-damage (THMD) coupled numerical model to systematically investigate the influence mechanisms of different natural fracture morphologies on fracture propagation. Results show that compared to scenarios without natural fractures, parallel natural fractures promote directional propagation of the mian fracture with an average width increase of 17.44% and <5% deflection probability. Intersecting fractures cause over 20% deflection, with significant width fluctuations during late-stage fracturing. Stepped network fractures induce multi-stage slip and discontinuous propagation, reducing the initiation pressure to 18.41 MPa and showing a branching probability of 55%–60%. Morphology-adapted optimization strategies are proposed: high-temperature, large-displacement injection for parallel fractures; stepped pressure boosting and nano-filtrate reducers to control fracture bifurcation for high-angle intersections; and composite proppants/tackifier for stepped networks. Field implementation demonstrate that optimized SC-CO2 fracturing increases effective stimulated volume by 13% and boosts peak daily oil production by 41%, confirming that morphology-adapted fracturing designs enhance fracture network stability and oil recovery efficiency.