The invention relates to a method for identifying salt-resistant capability of cotton by using death rate of leaf lower epidermic cells. The method comprises the steps of selecting leaves with identical thickness in a cotyledon stage of the cotton, and tearing the lower epidermis from the leaves gently; putting the prepared lower epidermis in a NaCl solution with a concentration of 3.5 M, and treating for 10-15 min; staining the epidermis treated by the salt solution for 5-10 min by using a 0.03-0.05% neutral red solution; immersing the intravitally stained epidermis in tap-water with a pH value a little higher than 7 for 3-5 min; observing death situation of the epidermic cells under an optical microscope; recording the deaths of the cells in the same area according to a principle that living cells are stained into cherry-red color while the dead cells cannot stained; and determining the salt-resistant capability of the cotton through the salt-resistant capability of leaf lower epidermic cells. The method can determine genotype salt-resistant capability rapidly and accurately, is labor-saving and time-saving time, is not influenced by seasons and environment, and increases identification efficiency.