A study of microwave-assisted extraction of lipid from three algal species in 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM][HSO4]), an imidazolium-based ionic liquid, was performed by evaluating the effects of microwave irradiation and ionic liquid on the extraction. The experimental results indicated that microwave irradiation could promote the extraction rate over 15 times for Chlorella sorokiniana, several hundred percent for Nannochloropsis salina and over 10 times for Galdieria sulphuraria when compared with the conventional solvent extraction method. [BMIM][HSO4] was an effective ionic liquid for the extraction of lipid from algae. The mineral acids could enhance the extraction of lipid from algae using [BMIM][HSO4]. The lipid product distribution showed not much difference between different species of algae. [BMIM][HSO4] was very stable under the extraction conditions. (C) 2016 Elsevier Ltd. All rights reserved.