A class of culture model with variableconsumption rate was considered.It was assumed that the consumption rate ofnutrition basis for the prayed species is δ1(s)=A+Bs+Cs2 and the consumption rate for the preying species with respect to the predatorspecies is δ2(x)=R+Px+Qx2.By the qualitative analysis ofthe culture model,the stability of steady states and the existence of a positive invariant set were discussed.The relationships among the parameters of themicroorganisms themselves,the coexistence of two microorganisms and theenvironment in the single food chain model with a variable consumption rate were presented.