Abstract: In this article, effect of cultural conditions such as temperature, pH, air conditions, culture medium and incubation time on the yield of toxin Vm-Pm by Vibrio mimicus were studied. Temperature had significant influence on the toxin Vm-Pm production, the optimal temperature for toxin Vm-Pm production was 30℃, and the optimal initial pH for the toxin Vm-Pm production was pH 6—8. The yield of toxin Vm-Pm was significantly enhanced when growing the strain with shaking. The yield of toxin Vm-Pm was the maximal during the mid- and late-logarithmic growth phases (when the strain was incubated for 36 hours), and was stable during the stationary growth phase(incubated for 72 hours). The yield of toxin in the improved medium containing 0.1% Fe2+ was twice more than that in the ordinary marine water agar, the result demonstrated that the availability of free iron in the medium had a significant influence on the production of toxin Vm-Pm,and also the pathogenesis of Vibrio mimicus.