Abstract: Gradient-structured tungsten alloys with spatially graded mechanical properties can effectively resolve the strength-ductility trade-off in conventional homogeneous tungsten alloys. The study separately develops a high-strength 93W-Ni-Fe-Mo alloy and a high-ductility 90W-Ni-Fe-Co alloy through optimized design. It employs co-sintering to fabricate gradient-structured tungsten alloys and systematically investigates the microstructural characteristics and mechanical properties of both W-Ni-Fe-Mo/Co alloy systems and the W-Ni-Fe gradient-structured alloy. Experimental findings demonstrate that the addition of Mo can effectively improve the tensile strength of 93W-Ni-Fe alloy and the introduction of Co can improve the ductility of 90W-Ni-Fe alloy. Fabricated via integrated pre-sintering and stepwise sintering at 1500 °C, the gradient tungsten alloy shows a ~20 μm interfacial layer. Tensile tests reveal 1180 MPa strength (15% elongation) in the high-strength zone and 920 MPa (48% elongation) in the high-ductility zone. The study identifies grain refinement and solid solution strengthening mechanisms induced by Mo doping. However, the introduction of a large amount (Mo addition ≥12%) canl lead to the formation of MoNi intermetallic compounds at the W/γ binder phase interface, which can damage the plasticity.