A composition having functions of clearing away lung heat, relieving cough and reducing phlegm and a preparing method thereof are disclosed. The composition includes honeysuckle bud and flower, liquorice root, milkvetch root, ginseng, boat-fruited sterculia seed, mint, tendrilleaf fritillary bulb and finger citron. The prepared composition has the functions of clearing away lung heat, relieving cough and reducing phlegm, utilizes synergistic effects of active components of a plurality of traditional Chinese medicines, is capable of tonifying qi and yin, promoting phlegm elimination, clearing away heat, detoxifying and dissolving turbidity, and can effectively relieve and treat throat dryness, pain and itch, dry cough, ungratifying coughing with phlegm, and other diseases caused by lung infection with contaminated air such as haze, smoking and dust transition. Production of effects is rapid. Preventing and treating effects are significant. The composition is also capable of increasing body fluid and expelling the pathogenic factor, is beneficial to health when the composition is drunk when air is contaminated, and can also be used for periodic maintenance at ordinary times.