Abstract: (NiFeCrNb)_100-xMo_x alloys（x=0, 0.25, 0.50, 1.00, wt%） were fabricated using selective laser melting（SLM） to investigate the influence of Mo content on their microstructure, magnetic properties and mechanical performance. The results show that the addition of an appropriate amount of Mo results in the formation of finely dispersed Mo-rich phases during SLM rapid solidification. These phases inhibit columnar grain growth and pin dislocations, optimize the microstructure and achieve a favorable balance between saturation magnetization（B_s） and coercivity（H_c）. The synergistic effect of Orowan strengthening and grain refinement significantly enhances the compressive strength, while residual stress is reduced to-53 MPa. However,excessive Mo causes coarsening of the Mo-rich phases formed during the solid-state phase transformation and grain boundary segregation. These coarse Mo-rich phases hinder magnetic domain wall movement, substantially increasing coercivity（H_c）. Concurrently, interfacial weakening and stress concentration lead to a significant deterioration in mechanical properties. This study elucidates the critical mechanism for achieving synergistic optimization of magnetic and mechanical properti es in SLM-processed alloys by controlling Mo content to regulate solidification segregation behavior and microstructural evolution.