Disclosed is a method of removing calcium from a hydrocarbon fraction using an extraction agent including 2-oxopropanal or derivatives thereof, the method including (S1) adding a hydrocarbon fraction with an extraction agent including 2-oxopropanal or derivatives thereof to give a mixture, (S2) converting an oil-soluble calcium compound into a water-soluble calcium compound by reacting the hydrocarbon fraction with the 2-oxopropanal or derivatives thereof, and (S3) removing the water-soluble calcium compound.