The present invention relates to a whitening composition comprising a youngia sonchifolia extract as an active ingredient and a method of preparing the youngia sonchifolia extract which has a superior whitening effect. The present invention especially has the superior whitening effect, has a good antioxidant effect, uses the youngia sonchifolia which was used as a food and a medicine for a long time, so that a problem related to tolerance and stability does not occur. Therefore, the whitening composition can be used in various ways including whitening cosmetics.(A1, A2) 0% alcohol(B1, B2) 50% alcohol(CC) Frozen and dried extract of Youngia sonchifolia(D1, D2) 100% alcohol(EE) Hot air dried extract of Youngia sonchifoliaCOPYRIGHT KIPO 2019