Wheat germplasm N9820, developed by our research group, is a resistant material to powdery mildew. In order to understand the resistant mechanism of wheat germplasm N9820 to powdery mildew infection, a suppression subtraction hybridization (SSH) cDNA library was constructed with cDNA from N9820 leaf inoculated with Blumeria graminis as the tester and cDNA from N9820 healthy leaf as the driver. A total of 122 positive clones were randomly chosen from the SSH-cDNA library. After screening of repeated and redundant sequences, 61 ESTs were acquired. Nucleic acid and protein homology search were performed using the BLAST (Basic Local Alignment Search Tool) program with the default settings at NCBI website (http://www.ncbi.nlm.nih.gov). BlastX results in nr-protein database revealed that 35 ESTs were highly homologous with known proteins involved in signal transduction, metabolism, cell structure, energy metabolism, transport, protein synthesis and processing, and disease resistance. BlastNr results showed that 47 ESTs had high identities with known ESTs, and 14 ESTs matched none in the nr-database. Compared with BlastX and BlastNr analysis, 19 ESTs were both in the nucleic acid and protein databases including 5 for energy metabolism, 2 for transport, 3 for protein synthesis and processing, and 2 for disease resistance. The most frequent sequence was ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit.