Abstract: In order to investigate the effects of neutral and alkaline salt stresses on growth, leaf electrolyte leakage, chlorophyll content, photosynthetic characteristics, proline content and organic acid metabolism, two Kentucky bluegrass (Poa pratensis) cultivars, ‘Midnight' (tolerant of saline-alkaline conditions) and ‘Voyager Ⅱ' (sensitive to saline-alkaline conditions) were subjected to neutral and alkaline salt treatments in hydroponic culture in growth chambers. The growth rate, chlorophyll content and photosynthesis decreased and leaf electrolyte leakage increased significantly under both types of salt stress, particularly under alkali stress. The tolerant cultivar showed less variation in response to the two salt stresses than the sensitive one. Leaf proline content only increased under neutral salt stress in both cultivars and no increase was observed under alkali stress. Oxalic acid was the only organic acid secreted by roots of either cultivar and increased significantly under alkali stress. The contents of leaf and root malic acid, citric acid and succinic acid in both cultivars hardly changed under neutral salt stress, but increased under alkali stress, with greater increase in ‘Midnight' than in ‘Voyager Ⅱ'. Alkaline salt stress caused more damage to Kentucky bluegrass than neutral salt stress. Under neutral salt stress, proline accumulation was the key metabolite associated with change in the osmotic potential. Under alkaline salt stress, organic acids were linked to regulation of pH values in the plant and the rhizosphere. Midnight, the cultivar tolerant of both types of salt stress, can maintain a higher photosynthesis rate and organic acid metabolism, and stronger ability to regulate pH in the plant and in the rhizosphere under neutral and alkaline salt stresses. In summary, Midnight possesses stronger tolerance to neutral and alkaline salt stresses in Kentucky bluegrass.