In this study, the curing behavior, physical properties and surface microstructures replication of the crosslinked liquid silicone rubber (LSR) obtained by the reactive injection molding process were evaluated. Two types of LSR with different hardness were used in this study. The physical properties of the LSR were measured for optical transmittance and tensile test. In addition, the influence of the reaction process on the density of LSR and the molecular weight of a crosslinking points was evaluated. As a result of reaction injection molding experiment and physical property evaluation, the molecular weight between the crosslinking points inside the molded article decreased due to extension of reaction time and increase in mold temperature. As a result, it is considered that the elastic modulus in the tensile test increased. Furthermore, the replication of micro-lens allay shape was analyzed. As a result of evaluating the surface replication ratio, all samples showed a replication ratio higher than 90%. The effect of mold temperature and reaction time on replication ratio could not be confirmed. It was suggested that higher replication ratio can be obtained by raising holding pressure and injection speed during molding.