In order to screen watermelon varieties in salt tolerance, germination experiments of 23 genotype watermelon varieties were done in 7 NaCl concentration . The results showed germination rate decreased with the NaCl concentration increasing and in mostly varieties were equal or increased comparing with those treated in 40-80mmol/L. Under 80-160mmol/L NaCl stress, the significant correlation was existed between 1000-grain weight and germination rate, among which the largest correlation coefficient was 0.606. Effects of the same NaCl concentration on the lateral root numbers, root length, root fresh weight, hypocotyls length and salinity injure index among different watermelon varieties were different ,and the results indicated that the tetraploid watermelon possessed higher salt tolerance than diploid. By the dendrogram of cluster analysis according to 5 principal components (germination rate, lateral root,et al), 23 varieties were affiliated with 4 clusters and the second cluster were identified to be best and salt tolerance of 6 varieties were better.