Abstract: The genes of plants were differently expressed in various phases of growth、development and multiplication and in different cells. In recent years, numerous methods used to investigate the gene differential expression were developed. Suppression Subtractive Hybridization （SSH）, developed in 1996, is a technique with high efficiency for isolation differently expressed genes at transcriptional level, combining subtractive hybridization with PCR, and its principle can be summarized as eliminating homologous sequences and enriching different sequences. SSH is able to isolate the differently expressed genes in one cycle, especially for genes expressed with low abundance. The features that high specificity, simple operation, low false positive rate and good repeatability make it widely applied in the differential expression genes separation despite of some defects. In recent years, SSH has been applied in studies on induced expression of plant disease resistant genes, with most focus on cDNA library construction and screen. The principle, main advantages and defects, and application progress in mechanism study on plants disease resistance were reviewed in this paper.