Seedling stage is an important stage for the morphology of rapeseed plants, and salinity stress is one of the main factors affecting its seedling morphology, so screening out salinity-tolerant germplasm in the seedling process is of great significance to rapeseed production and research. In this study, 286 kale-type Brassica napus lines were identified for salinity tolerance during the seedling stage, and the number of leaves, green leaves, green leaf ratio, plant height, root length, root weight and other indexes were determined by hydroponic test under salinity stress treatments, and different genotypes of seedling stage oilseed rape germplasm were identified by the comprehensive evaluation value of saline and alkali stress (D-value), screening analysis of extreme materials, correlation, principal component, subordinate function, frequency number analysis and stepwise regression analysis. A comprehensive evaluation model of salinity tolerance was established for different genotypes of seedling oilseed rape germplasm and suitable evaluation and identification indexes were screened out. The correlation coefficients between the number of leaves and plant height were not significant, and the number of leaves was negatively correlated with the plant height and the number of green leaves under saline and alkaline stress, while the correlation coefficients between the number of leaves and the number of green leaves were negatively correlated with the number of green leaves. The seven salinity tolerance indexes were combined into four principal components using principal component analysis, which could represent 88.349% of the original data information of salinity tolerance in oilseed rape. Based on the relative importance (weight) of the four principal components, the combined salinity tolerance evaluation value (D value) of different genotypes was obtained. Combined with affiliation function analysis and extreme material screening analysis, four alkali-resistant kale-type oilseed rape germplasm and four saline-sensitive germplasm were screened out. The results of stepwise regression analysis showed that the salinity tolerance of kale-type oilseed rape germplasm resources could be preliminarily determined by measuring the number of green leaves, green leaf ratio, above-ground weight, root length and root weight at the seedling stage, and then estimating the D-value of the germplasm resources through regression equations.