The invention discloses a culture medium. The culture medium includes a watermelon juice, a Hami melon juice, a sand pear juice, a muskmelon juice, tea polyphenol, potassium nitrate, iron phosphate, ammonium nitrate, calcium nitrate, magnesium nitrate, potassium iodate, sodium borate, potassium molybdate, zinc chloride, manganous sulfate, copper chloride, ferric nitrate, vitamins, amino acids, indolebutyric acid, gibberellin, 6-benzyladenine, isopentenylaminopurine, naphthylacetic acid, agar, kinetin, a cosolvent, a dispersant, a compatilizer, a stabilizer, an antibacterial agent and water. The culture medium has the advantages of reasonable collocation, comprehensive nutrition, rapid promotion of roots and stems, increase of the transplanting survival rate, promotion of the accumulation of flavonoids, and improvement of the economic benefit; and a preparation method of the culture medium has the advantages of simplicity in operation, and easiness in realization of industrial, normalized and standardized production.