The transport and placement of proppant significantly affect fracture conductivity and effectiveness. Influenced by reservoir heterogeneity and non-uniform distribution of net pressure within the fracture, the hydraulic fracture width gradually decreases from the fracture mouth to the tip, and the fracture propagation exhibits a certain degree of tortuosity. Addressing the issue that existing research is mostly based on parallel plate or single tortuous fracture models, which cannot truly reflect the coexistence of width attenuation along the fracture and spatial tortuosity, a complex fracture model incorporating both wedge-shaped contraction and multi-stage tortuosity features was constructed. Using the dense discrete phase model (DDPM), the limitations of traditional discrete phase models in handling high-concentration particle collision and accumulation behaviors were overcome, enabling accurate capture of flow separation and collision-accumulation phenomena of proppant within variable-cross-section tortuous channels. The study found that under the same conditions, when the fracture tortuosity angle is 0°, proppant transport and placement are better; when the tortuosity angle is 30°, proppant can still break through the tortuous position and migrate forward, but the suspension capacity is greatly reduced, forming a proppant bank; when the tortuosity angle is 60°, proppant struggles to pass the tortuous position and accumulates in front of it, forming a proppant bank; increasing injection rate, raising carrier fluid viscosity, and reducing proppant particle size all facilitate proppant breaking through the tortuous position and migrating deeper into the fracture; excessively high proppant concentration increases the risk of sand plugging—when the concentration increases from 5% to 15%, the height of the proppant bank formed by sedimentation increases by 1 630%, while proppant agglomerates in the suspension zone, hindering subsequent proppant entry into the fracture. The results of this study will provide theoretical support and guidance for the design and optimization of pumping schedules in field fracturing operations.