In order to grasp the influences of nutrients and sea water reuse on growth and toxin productivty of the Alexandrium minutum, single factor experiments were used to observe the influences of the concentrition of nitrogen (NaNO₃), phosphorus (NaH₂PO₄), trace element (FeCl₃, Na₂EDTA, CuSO₄, Na₂MoO₄, ZnSO₄, CoCl₂, MnCl₂), vitamin (Vitamin B₁₂, Vitamin H, Vitamin B₁), carbon (NaHCO₃) and the style of sea water (new or reuse) on the growth, toxin content (μmol/L) and toxin constitution of Alexandrium minutum C4. The results showed that nitrogen and phosphorus had a significant effect on the total toxin content (μmol/L), while others had non-significant effect (μmol/L); nitrogen, phosphorus, trace element and carbon had a significant effect on the ratio of GTX1/4(GTX1+GTX4) to total toxin content(GTX1+GTX2+GTX3+GTX4), while vitamin and sea water reuse had non-significant effect on that ratio. There was a positive correlation between the concentration of toxin and nitrogen when the nitrogen concentrition was between 0 and 883 μmol/L, and then toxin content stayed invariant with the increase of nitrogen. However, with the increase of phosphorus concentrition from 0 to 145.2 μmol/L, the toxin content increased at first, then reduced,and stayed invariant in the end.The optimal conditions for the toxin production were nitrogen 883 μmol/L, phosphorus 18.15 μmol/L, trace element one half of that in the f/2 medium and carbon free.