The invention relates to a method for extracting oil from microalgae by utilizing
ionic liquid, which comprises the following steps of: 1) preparing functionalized
ionic liquid; 2) adding a certain quantity of microalgae into the
ionic liquid and magnetically agitating through heating to dissolve the microalgae; 3) extracting oil in an ionic liquid mixture by using an
organic solvent; and 4) adding a certain quantity of water into an ionic
liquid phase after the oil is extracted, removing a water phase through
evaporation, realizing the regeneration of the ionic liquid and reusing the ionic liquid. According to the method, the ionic liquid is utilized to dissolve the microalgae so as to extract the oil, almost has no
vapor pressure and has the characteristics of greenness, environment friendliness and the designability; the
cell wall of a microalgae can be remarkably damaged to release oil in a microalgae
cell or on the
cell wall; the oil is easily separated from the ionic liquid, so that the extraction rate of the
oil can be remarkably improved; and the ionic liquid can be recycled through a water
dilution method. The method can become a new process for microalgae oil extraction.