Abstract: In this paper the effects of complex alkali-saline stress on 4 varieties of cool season Poa Pratensis were compared during the seeds germination and seedling stage. The findings are as follows: lower concentration of complex alkali-saline promote germination and growth of Poa Pratensis; However germination percentage and growth of Poa Pratensis were restrained prominently with increasing of complex alkali-saline contents And the stress was stronger for growth of radical than that of plumule with increasing of complex alkali-saline concentrations. The results of complex alkali-saline stress on 4 varieties during seedling stage showed that the enzyme activities of SOD、CAT and POD, free proline content increased under lower concentrations of complex alkali-saline, and reached the peak under medium concentration, then decreased under serious stress. In addition, MDA content increased gradually with the increase of complex alkali-saline concentrations. By analyzing comprehensively these physiological indexes, the result indicated that the order of the alkali-saline tolerance of seeds of 4 varieties was ‘Midnight’ > ‘Bulin’ > ‘Baron ’ > ‘Merit’．