Various $alpha$-silicon carbied and colloidal graphite particles were sintered at 155$0^{circ}C$ in vacuum atmosphere by reaction bonding sintering method, and the physical properties and microstructural analysis of specimen were investigated. With decreasing particle size, sintered density and 3-point bending strength of materials were increased and 3.2${mu}{ extrm}{m}$ specimen showed high density and strength, 3.05g/㎤, 40kg/$ extrm{mm}^2$, respectively. The results of X-ray diffractometer and optical micrographs analysis showed that graphite and silicon melt reacted to convert to fine $eta$-SiC particle and the body was changed to dense material.