The aim of our work is to synthesize a new phosphorus tri-functional epoxy resin tri-glycidyl ether tri-mercaptoethanol of phosphorus (TGETMEP) in two stages. In the first stage, we got the precursor molecule of the epoxy matrix tri-mercaptoethanol phosphate (METR). The second step led us to the synthesis of tri-functional resin TMEP condensation with epichlorohydrin. The standard TGETMEP resin was characterized by the Fourier infrared transformation (FTIR) and nuclear magnetic resonance (NMR), on one hand. The viscosimetric analysis was investigated by the Hebbelod capillary viscometer and rheometer Rheomat 01, on the other hand. The cross-linked resins and tertiary formulated composites have been studied by the rheometer 01 which was observed by means of SEM.