In the course of teaching of the fermentation kinetics, these doubts were cleared up by attempts to get the good result of the classroom teaching, which are the biomass growth rate and specific growth rate, the biomass actual yield coefficient (Yx/s) and the theoretical yield coefficient of growth (Ygs), the actual product yield coefficient (Yp/s) and the theoretical product yield coefficient (Yps), specific growth rate control in fed-batch fermentation and other difficulties.