Abstract: Objective:To analyze the influence of a new kind of anticancer biological preparation, anticancer bioactive peptide (ACBP), on gene expression profile alteration of the human gastric cancer cell line BGC- 823 using microarray tech -nique, clarify its anticancer mechanism and test its validity for part of the differentially expressed genes by using RT-PCR method. Methods:Two cDNA microarrays, containing 400 genes and 648 genes, were prepared by spotting purified PCR products onto specially treated glass slides. BGC-823 cells treated with different concentrations of ACBP at different times were used as the experimental group and BGC-823 cells treated with saline were used as the control group. After the best action time and concentration were determined, probes were made as follows: total RNA was extracted and reverse tran-scribed into cDNA for both the experimental and control groups, and labeled with Cy5 and Cy3 fluorescent dyes, respective -ly. These were then hybridized onto microarrays. Subsequently, data were analyzed using bioinformatics. RT-PCR was used to test candidate genes p 15and HSP701 B. Results:There were a total of47differentially expressed genes on the two microarrays: 27were up-regulated and20were down-regulated. These genes were classified into several categories: cell cycle, metabolic enzymes, immune related genes, cell apoptosis and tumor suppressor genes, including HSP701 B, HSP75, HSP 90, PLD 2, IEX- 1L, IAP3, Ubch5c, γ-IFN, p15. RT-PCR results showed that p 15 was up-regulated and HSP701 B was down-regulated in the experimental group compared with the control group, which also confirmed the validi -ty of the microarrays. Conclusion : Anticancer bioactive peptide has the function of regulating the gene expression of human gastric cancer cells,such as tumor suppressor genes and heat shock protein family members. Microarrays can provide a powerful molecular basis for clarifying the mechanism of anticancer drugs.