To balance the utilization of rare earth (RE) resource and develop Ce-based permanent magnets with high performance/cost ratio, the role of La substitution in the melt-spun (Ce 1− x La x ) y Fe 14 B ( x  = 0–0.4, and 0.5; y  = 2–4) alloys has been investigated. It has been confirmed that the hard magnetic properties of Ce-based magnets can be effectively enhanced by partial substitution of La. The maximum ( BH ) max of (Ce,La)–Fe–B alloys can be obtained at a Ce:La atomic ratio of 7:3. The lattice parameters and Curie temperature of the hard magnetic (Ce/La) 2 Fe 14 B phase increase linearly with increasing La content. Three different alloy systems with y  = 2, 2.5 and 3 show similar behavior of magnetic properties dependences on La. In the RE-rich compositions, La substitution for Ce can effectively inhibit the precipitation of the CeFe 2 phase. A solid solution, Ce(La) phase with a space group of Fm-3m, appears in the (Ce 0.7 La 0.3 ) y Fe 14 B alloys with y ≥ 3.5. A good combination of magnetic properties with H cj  = 345 kA/m, J 5T  = 1.03 T, J r  = 0.60 T, and ( BH ) max = 6.3 MGOe is obtained in (Ce 0.7 La 0.3 ) 2.5 Fe 14 B alloy. In addition, 30 at.% La substitution for Ce can significantly refine the grains, resulting in the enhancement of exchange coupling interaction. The present finding is beneficial for designing new and low-cost magnetic materials.