DNA methylation is one of the epigenetic mechanisms that regulate plant growth, development and stress gene expression. In this study, we used 5azaC, a DNA methylation inhibitor with different concentrations, to treat spring wheat seeds with different salt treatments. We analyzed the effects of 5azaC on seed germination and DNA methylation changes after salt stress to explore the correlation between DNA methylation and salt tolerance of wheat. The results showed that: (1) 5azaC can significantly inhibit root length and reduce fresh weight and dry weight. (2) MSAP analysis showed that the methylation levels increased after salt stress alone, but the methylation level of 5azaC pretreated materials after salt stress showed a downward trend. (3) After salt stress, DNA demethylation and DNA methylation occurred simultaneously in the genome. The rate of DNA demethylation increased for saltsensitive cultivar ‘Xinchun 6’, while the DNA methylation rate decreased. Both rates of DNA demethylation and DNA methylation increased for salttolerant cultivar ‘Xinchun 11’, but the rate of demethylation was higher than that of DNA methylation. The results showed that the main change of DNA methylation in wheat leaves was DNA demethylation after salt stress. 5azaC increased the rate of DNA demethylation under salt stress. (4) Sequence analysis of DNA methylation modification sites found that DNA methylation modifications were present in ribosomal subunit proteins, protein kinases, and transposon sequences, indicating that salt stress could be resisted by multiple metabolic pathways.