Oneyearsold seedling of Prunus mume ‘Feng hou’, grafted seedling of P. mume ‘Feng hou’ and Prunus sibirica treated by NaCl were studied to explain their resistance to salt stress. The soil salt contents were set as 0(CK), 0.3%, 0.6%, 0.9%, 1.2% and 1.5% respectively. Salt injury index, membrane permeability, antioxidant enzyme activity and osmotic adjustment substance contents were detected. and the physiological indexes of three plants leaves were evaluated synthetically by membership function law to determine their salt tolerance ability and to provide the theory basis for the popularization and application in the north, the choice of breeding methods, and the choice of stock selection of P. mume. The results showed as follows: (1) with the increase of soil NaCl content, salt injury index and salt injury rate of seedling of P. mume‘Feng hou’, grafted seedling of P. mume‘Feng hou’and P. sibirica increased, which NaCl contents are 0.545%, 0.695% and 0.705% when their salt injury index is 50%. It indicates that the resistance of three plants to NaCl ranked from P. sibirica, grafted seedling of P. mume ‘Feng hou’ to seedling of P. mume ‘Feng hou’. (2) With the stress days lengthened of soil NaCl, relative conductivity and MDA contents increased firstly and then decreased; POD activity increased but part of grafted seedling of P. mume ‘Feng hou’ and P. sibirica increased firstly and then decreased; Soluble sugar content of seedling of P. mume ‘Feng hou’ increased, Soluble sugar content of grafted seedling of P. mume ‘Feng hou’ and P. sibirica decreased firstly and then increased but part of them increased firstly and then decreased. (3) We synthetically assess the resistance of three plants to NaCl ranked from P. sibirica, grafted seedling of P. mume ‘Feng hou’ to seedling of P. mume ‘Feng hou’ by membership function law, which is the same as the result of salt injury index analysis. The study found that the injured degree of three plants leaves deepened with the salt stress concentration elevated, but they can produce certain adaptability to the lower and medium salt stress. The salt resistance of seedling of P. mume ‘Feng hou’ is more stronger than grafted seedling of P. mume ‘Feng hou’ when it was treated. The strong salt tolerance of P. sibirica as root stock, explains that grafting can improve the salt tolerance of P. mume.