Abstract: To explore the adaptive capacity of seed germination and seedling growth of Haloxylon ammodendron under osmotic stress, seed germination percent and seedling growth of H. ammodendron were investigated using PEG and sodium nitroprusside (SNP). Results showed that seed germination percent of H. ammodendron was improved, as well as seedling root and stem growth, and dry weigh of seedlings increased with SNP treatment under PEG stress. Experimental data using SNP (300 μmol/L) was significant especially, and seed germination percent, seedling roots and stem elongate growth increased by 13%, 34% and 21% than control under -0.5 MPa conditions. Seed germination of H. ammodendron was completely inhibited under -1.5 MPa conditions, and seed germination rate was more than 40% using SNP treatment.