Abstract: Some physiological and biochemical changes in wheat seed or seedling from seed priming (treated with -0. 8 MPa or -1.2 MPa PEG-6000) were studied. Reponses of wheat Jin 33 and 84G6 to osmotic stress were compared. The data showed that seed priming improved seed germination under osmotic stress, decreased seed electrode leakage, increased seed soluble protein content, enhanced activity of PAL and POD of Jin 33 and 84G6 seed,CAT of Jin 33 seed,and activity of PAL, POD,and CAT of both Jin 33 and 84G6 seedlings. Priming with -1.2 MPa PEG -6000 had a slightly stronger effect on seed,and Jin 33 gave a better response to PEG priming. Role of seed priming in improving plant osmotic resistance were discussed.