In the SHS process, compaction pressure on the reactant pellet is an important part influencing the thermal conductivity of the reactant. The thermal conductivity of the reactant affects the heat propagation and the heat loss during the ignition and wave propagation of the reaction. The objective of this work was to study the effect of compaction pressure on the microstructure of the synthesized product. An Ni/Al mixture and Ti layer were compacted to produce 100 MPa, 150 MPa and 200 MPa on the pellets and ignited to initiate the SHS process. The microstructure of the synthesized product was observed using XRD and SEM. Microstructure analysis indicated that several intermetallic phases have existed in the bilayer product as the results of reactions between Ni/Al and Ti. The prorosity of synthesized product was also varied with the compaction pressure of the reactants.