Based on Grove model of CVD(chemical vapor deposition) and Fick’s first law, we propose and build the RPCVD(reduced pressure chemical vapor deposition) growth kinetics model of GeSi/Si heterojunction materials. Different from previous SiGe/Si kinetics model, which only considers surface reaction controlling mechanism, our model simultaneously considers two controlling mechanisms: surface reaction and vapor transport. We also consider the model at these two controlling mechanism limits. This model is suitable for charactering the growth of both strained GeSi/Si heterojunction materials at low temperatures and relaxed GeSi/Si heterojunction materials at high temperatures. The calculated value of the model is compared with experimental results. Whether for the growth of strained SiGe at low temperature of 625 ℃, or for the growth of relaxed SiGe at high temperature of 900 ℃, the model error are both lower than 10%, which is the subject technical target.