High-performance materials are in strong demand in the electronics and automotive industries. Cu-Ni-Si alloys are widely used owing to their excellent combination of strength and electrical conductivity, whereas 1010 steel provides superior formability, high elastic modulus, and cost-effectiveness. Integrating these materials into laminated bimetallic composites represents a promising strategy for achieving structural-functional integration, thereby overcoming the trade-offs inherent in single-component metals. However, fabrication of such composites remains challenging, primarily due to poor wettability and limited mutual solubility between Cu and Fe, which often result in weak interfacial bonding and coarse as-cast microstructures. Therefore, the development of effective fabrication methods and appropriate post-processing routes to tailor microstructure and optimize mechanical properties is essential for industrial application. In this study, Cu-Ni-Si/1010 steel laminated bimetallic composite was successfully fabricated via continuous solid-liquid bonding method. To investigate the effects of annealing and cold rolling followed by annealing on microstructural evolution and mechanical behavior, the composites were subjected to four conditions: as-cast (sample S1), direct annealing at 450 °C (sample S2), 70% cold rolling followed by annealing at 450 °C (sample S3), and 70% cold rolling (sample S4). Microstructural and mechanical characterization was performed using OM, SEM, TEM, and tensile testing to elucidate the relationships among processing parameters, interfacial characteristics, and strengthening mechanisms. The Cu-Ni-Si layer in sample S1 exhibits coarse columnar grains, with a minor β-Ni₃Si phase located at α-Cu grain boundaries. Direct annealing promotes the formation of nanoscale δ-Ni₂Si precipitates within the α-Cu matrix, contributing to strengthening. In contrast, the combined cold rolling and annealing treatment induces more pronounced microstructural evolution: severe plastic deformation increases dislocation density and refines the grain structure into the fibrous morphology due to incomplete recrystallization. No brittle intermetallic compounds are observed at the interface under any condition. Samples S3 and S4 exhibit wavy, well-bonded interfaces, indicating enhanced interfacial diffusion and metallurgical bonding. Tensile testing shows that sample S3 achieves the highest ultimate tensile strength (613 MPa), significantly exceeding those of sample S1 (379 MPa) and sample S2 (415 MPa), which is attributed to the synergistic effects of work hardening, precipitation strengthening, and hetero-deformation induced strengthening. Although ductility decreases slightly in sample S3, the elongation remains relatively high at 18.4%, whereas sample S4 exhibits the lowest elongation (12.6%), which is detrimental to subsequent forming. Importantly, all samples fracture within the matrix without interfacial delamination, confirming robust metallurgical bonding. These results indicate that direct annealing enhances both strength and ductility in Cu-Ni-Si/1010 steel laminated bimetallic composites, while cold rolling followed by annealing is an effective strategy for substantially increasing strength while preserving interfacial integrity.