Microalgal lipid is a very important bioenergy and rapid analysis for the content of microalgal lipid is much significant to the industrialization of energy microalgae. In the present study,sulf-phospho-vanillin reaction was used to detect the intracellular lipid content of an isolated Scenedesmus sp. when it was cultured with different concentration of glucose,nitrogen or phosphorus,with the method of organic solvent extraction as control. Meanwhile,other microalgaes such as Chlorella sp.,Cyclotella sp.,Fragilaria sp.,were analysed in the total lipid content by sulf-phospho-vanillin reaction. Result showed that sulf-phospho-vanillin reaction was a rapid and accurate analysis method for the determination of lipid content of mciroalgae.