The CMV promoter driven luciferase reporter gene coding plasmid (pcDNA-luc) was constructed and used as a model for DNA immunization study. Expression of the recombinant luciferase protein was confirmed in vitro in RTG-2 cell line before using in vivo study in olive flounder. In dose response study, the maximum expression of the luciferase gene was found in the group injected with 10-15μg of plasmid DNA. The kinetic study showed that the luciferase gene expression was reached at the maximum level at one day after injection and slightly decreased after then but significantly high level of expression was sustained until the conducted experiment of 7 days. In the study of tissue distribution of gene expression, it was found that luciferase gene was expressed at the significant level in immune organs such as gill and spleen, located far from the injected site, suggesting the systemic distribution of the intramuscularly injected DNA in olive flounder