Abstract: In this paper, a method for calculating dosage regimen on two compartment model drugs administered by "intravenous injection+intravenous infusion" is described. The dosage regimen rising the method Will give effective drug blood concentrations all the time (from the beginning to the end) during which the drug is administered.Method 1. When C^max/C^min≥K₁₀/β, the D and K₀ are taken to satisfy (K₁₀/β)VC^min≤D≤VC^maxK₁₀VC^min≤K₀≤βDwhere C^max is the maximum-quantify of the effective range of drug blood concentrations, C^min is the minimum quantity. D is the dose of intravenous injection, K₀ is the zero order rate constant of intravenous infusion, V is the volume of central compartment, K₁₀ is the first order elimination rate constant from the central compartment, β is the slow disposition rate constant.Method 2. The D is taken to satisfy VC^minmaxand if K₁₀VC^max<(α+β-αβ/K₁₀)D,then the K₀ is taken to satisfy maxK₁₀VC^min, βD010VC^max, else the K₀ is taken to satisfy maxK₁₀VC^min,βD0<(α+β-αβ/K₁₀)D And the D and Ko also satisfy K₀/(VK₁₀)-(1/VK₁₀)·1-K₁₀/α)^α/(α-β)/(K₁₀/β-1)^β/(α-β)·(K₀-βD)^α/(α-β)/(αD-K₀)^β/(α-β)≥C^min) where α is the fast disposition rate constant. Method 3. The D is taken to satisfy VC^min≤D≤VC^max,And if K₁₀VC^max<αD,then the K₀ is taken to satisfy (α+β-αβ/K₁₀)D≤K₀≤K₁₀VC^max,else the K₀ is taken to satisfy (i>α+β-αβ/K₁₀)D≤K₀≤αD.Method 4. When C^max/C^min≥α/K₁₀, the D and K₀ are taken to satisfyVC^min≤D≤(K₁₀/α)VC^maxαD≤K₀≤K₁₀VC^max.