In order to determine the suitable cultivation area, improve the cultivation technology and guarantee the medicinal quality of G . longituba, the effects of soil pH (4.5, 5.5, 6.5, 7.5, 8.5 and 9.5) on growth, physiological characteristics and medicinal quality of G . longituba were studied with exogenous NaOH and H₂SO₄ as pH regulators. The results showed that G . longituba could grow normally in soil with pH from 4.5 to 8.5, but could not survive in soil with pH 9.5. The growth indicators of G . longituba including leaf length, leaf width, pitch interval, internode number, stem length and dry matter accumulation increased initially and then decreased when soil pH varied from 4.5 to 8.5, peaking at pH 6.5. The activities of SOD, POD, CAT and the content of chlorophyll in G . longituba leaves were first increased and then decreased, while the contents of soluble sugar, soluble protein, free amino acid and malondialdehyde in G . longituba leaves were reduced initially, and then increased. The contents of ethanol-soluble extractives were greater than 250 mg/g, conforming to the quality criterion in Chinese Pharmacopoeia 2015. The variation trend of total flavonoids, oleanolic acid and ursolic acid contents of G . longituba were similar to those of growth indexes; the highest contents of total flavone, oleanolic acid and ursolic acid were appeared in pH 6.5, with the contents of 15.73, 0.71 and 2.87 mg/g, respectively. The contents of chlorogenic acid or caffeic acid in pH 6.5, 7.5 and 8.5 treatments showed no significant difference, but generally higher than other treatments. The highest content of rosmarinic acid (2.26 mg/g) was observed in pH 7.5 treatment. It is concluded that soil pH has significant influence on growth, physiological characteristics and medicinal quality of G . longituba, and neutral or slightly acidic soil is conducive to the growth and the medicinal quality of G . longituba.