The synthesis process, strength and electric property of PMMA and carbon nanotube in situ composite are investigated. The results show that carbon nanotube may join the chain reaction in polymerization of MMA. The reaction not only affects the process and the tensile strength of composite, but also affects the dispersity of carbon nanotubes in PMMA matrix. If the reaction of carbon nanotube joining polymerization of MMA is postponed properly, the strength of the composite could be enhanced. With additi...