Abstract: The biomass of Spirulina maxima increased 24.6%~25.7% when being added 1g/m³liquid triacontanol into Zarrouk culture medium;the biomass of Spirulina maxima still increased 4.43%~4.92% even if content of NaHCO₃ in the medium was decreased half(Test 2).The content of carbohydrate increased 11.9%~16.0% in Test 1 and 5.7%~8.3% in Test 2 respectively.The content of chlorophyll a increased 45.8%~63.3%;the total content of protein keptinvariable basically,but hydrosoluble protein was obviously improved from 36% to 60% or so,while non-hydro soluble protein decreased from 30% to 10% or so.Moreover,39.76% rate of increase of biomass was got when adding 1 g/m³liquid triacontanol on a large-scale culture at Spirulina produce base,higher than on a little-scale at laboratory,but decreased 12% when adding solid triacont anol.So a conclusion can been obtained:the Spirulina biomass and biochemical composition were greatly improved when adding liquid triacontanolinto the culture medium.