Carbon fiber reinforced plastics are prepared by compression molding technique, using epoxy resin impregnated prepregs. The most critical farctor of the process is the pressing time, i.e., the time between placing the loaded mold onto a heating plate and applying pressure to close the mold. A systematic analysis on the compression moldin process was done by evaluating the curing reaction processes and the viscosity change during the compression molding operation. The epoxy curing reaction kinetics were determined by a dynamic Differential Scanning Calorimetry (DSC) method on a epoxy resin-nadic methyl anhydride (NMA)-benzyl dimethyl amine (BDMA) system. The viscoity change at dynamic luring condition was measured by Rheometrics Mechanical Spectrometer (RMS) and Dynamic Mechanical Analyser (DMA). The correlation between the degree of curing rind the viscosity was obtained from the kinetics and empirical viscosity data through a multivariable non-linear regression. A simulation model was established so that one can predict the optimum pressing time at a given optimum viscosity point for the compression molding.