Fluorescent material containing Si was prepared from organosilane such as diphenylsilane by micro-reactor under the condition of supercritical fluid. Generally, supercritical fluid is obtained under high pressure and high temperature condition using high pressure reactor which is usually big and heavy apparatus. But, supercritical fluid condition was easily and safely obtained using micro-reactor system. The product was dark yellow discus material. PL spectral of the product was similar to that of porous silicon which was known to be composed of Q-dot silicon nano particle.