A Monte Carlo simulation on the ternary self-condensing vinyl polymerization system under the semi-batch mode is presented, where reactants are composed of comonomers (inimers and monomers) and multi-functionality core initiators. For the semi-batch process in the system, we mainly consider the influence of three feeding ways on the average polymeric quantities (weight-average molecular weight and polydispersity index) of hyperbranched polymers, where core initiators and comonomers are fed into the reactor at different time (or equivalently, at different conversions of vinyl group). As expected, the semi-batch process has a significant effect on the average properties of polymers, and therefore the feeding schedule can be predetermined to prepare polymers with desired properties.