Abstract: Dihydroartcmisinine (DHA) is a derivative of qinghaosu(arternisinine), which is an antimalarial drug. DHA was given to mice inoculated with Plasmodium berhgei ANKA strain by intramuscular injection. Within proper dose range, the dose-effect and time-effect curves of DHA against the malaria can be described by y= 4.9960+2.9536 x and y= 7.2654-0.3414 t, respectively, where y is the estimated value of parasitemia suppressing rate in probit ;x is log dose; t is the period since drug administration im. Accordingly,the ED₅₀= 1.00± 0.13 mg/kg and the time of half-effect was 6.6 h, when the dose was 5.0 mg/kg ira. The elimination rate constant of the effective dose in vivo was 0.2662h^-1with a half-life of 2.6 h.