Soil salinization-alkalization are widespread global issues. Cultivating salt-alkali tolerant plants is a crucial strategy for the remediation and management of saline-alkali lands. In this study， twelve accessions of Brassica napus were used to investigate the effects of saline-alkali stress during seed germination. Stress was imposed using a mixture of NaHCO₃ and Na₂CO₃ at a molar ratio of 9∶1， with seven concentrations including the control （0， CK）， 10， 20， 30， 40， 50， and 60 mmol/L. The results showed that the germination potential and germination rate of rapeseed did not differ significantly from the control under 10-40 mmol/L saline-alkali stress， but decreased significantly at 50-60 mmol/L. Compared with the control， germination speed， root length， hypocotyl length， and vigor index all decreased significantly with increasing stress concentration. Under 10-40 mmol/L stress， the activities of peroxidase （POD） and catalase （CAT） increased with rising concentrations， peaking at 40 mmol/L， and declined at 50 mmol/L. Malondialdehyde （MDA） content showed no significant difference compared to the control under any of the concentration stresses. Through significance analysis， 40 mmol/L was identified as a suitable concentration for large-scale screening of saline-alkali tolerant rapeseed germplasm. Using this concentration， 87 core accessions of Brassica napus were evaluated for saline-alkali tolerance. The relative germination potential， relative germination rate， relative root length， relative fresh weight， and relative hypocotyl length all exhibited normal distributions， indicating abundant genetic variation in saline-alkali tolerance among the materials. Correlation analysis revealed a highly significant positive correlation between germination potential and germination rate. Both traits were positively correlated with hypocotyl length but showed a highly significant negative correlation with root length. Principal component analysis showed that the first three principal components cumulatively explained 84.16% of the total variance， with relative germination potential， relative germination rate， and relative fresh weight accounting for 43.30% of the variation. Based on D-values from cluster analysis， the 87 accessions were classified into five groups， from which one highly tolerant， five tolerant， and three sensitive germplasms were identified. This study established a reliable method for evaluating salt-alkali tolerance of B. napus and identified tolerant germplasms， which provides methods and materials for the identification of salt-alkali tolerance and variety breeding of B. napus， and lays a foundation for elucidating the molecular mechanism underlying salt-alkali tolerance in B. napus.