The addition of hybrid ceramic reinforcing phases provides the possibility of regulating the in-situ reaction and effective strengthening in laser additive manufactured aluminum matrix composites. In this work, aluminum matrix composites reinforced with (ZrC+TiC) solid solution ceramics with micro/nanoscale microstructural features are fabricated by laser powder bed fusion (LPBF). The influence of laser power and reinforcement fraction on the manufacturing quality, microstructure formation and the mechanical properties of the LPBF-fabricated (ZrC+TiC)/Al composites are investigated. The reaction mechanism between the ZrC and TiC ceramics in the LPBF process is revealed. The tensile properties of the (ZrC+TiC)/Al composites with different (ZrC+TiC) contents prepared at optimal process parameters are compared. During the LPBF process, the ZrC and TiC ceramics are incompletely melted. On the ceramic particles, a thin (Ti,Zr)C layer formed and large amounts of nanoparticles precipitated via a dissolution-precipitation mechanism. When the laser power increases from 375 W to 425 W, the manufacturing quality, microhardness, tensile and wear properties of the (ZrC+TiC)/Al composites increase. With the hybrid ceramic content raising from 10 to 20 wt.%, the laser absorption behavior is enhanced, and the nano-particle fraction increases. The micro/nano hardness of the composites with 20 wt.% ceramic content, reaches 120 HV0.2 and 1.33 GPa, respectively. The tensile strength of 10 wt.% (ZrC+TiC)/Al composites prepared at optimal processing parameters reaches a high strength value of ~227 MPa with a uniform elongation of ~6.7%, which is three times higher than that of the unreinforced Al-matrix. This is ascribed to the combined effects of Orowan strengthening, coefficient of thermal expansion (CTE) mismatch strengthening, load-bearing strengthening and grain refinement strengthening.