Abstract: The seeds of four important desert plants: Haloxylon ammodendron, Reaumuria soongorica, Ceratoides latens and Suaeda glauca were collected from the Alashan arid desert, Inner Mongolia. The effects of drought stress on seed germination under PEG treatment and of germination recovery under optimal conditions after presoaking with PEG solution were studied in a series of laboratory tests. The germination and radical growth of the four desert plant species were subjected to different degrees of inhibition with reduced osmotic potential of a series of PEG solutions. The lower the osmotic potential, the more apparent the inhibitory effect. However, slight drought stress promoted the germination of R. soongorica, C. latens and S. glauca, improved the germination index of R. soongorica and S. glauca, and stimulated the radical growth of the four desert plants. The lowest thresholds of osmotic potential for germination were -3.0 (H. ammodendron), -2.1 (R. soongorica and C. latens) and -1.5 MPa (S. glauca). H. ammodendron had the strongest drought resistance, and S. glauca, the weakest. Under optimal conditions, the seeds presoaked with PEG solution recovered their germination after drought stress was relieved. The seeds presoaked for longer suffered greater damage from drought stress, and at the longest times germination was suppressed completely. Shorter duration presoaking improved germination percentage and index of R. soongorica significantly, stimulated the radical growth of H. ammodendron, R. soongorica and C. latens, but suppressed the radical growth of S. glauca.