The invention discloses a method for preparing raspberry ketone under the catalysis of multi-sulfonic functionalized ionic liquid. According to the method, phenol and methyl vinyl ketone are used as raw materials and the multi-sulfonic functionalized ionic liquid is used as a catalyst for selective catalytic synthesis of raspberry ketone. The ionic catalyst has the advantages of high acid value, low synthesis cost, good catalysis efficiency and reaction activity at room temperature compared with conventional ionic catalysts.