Inspite of students` curosity and social need for genetic engineering there are not actual experiments related with it in biology textbook of high school. A basic laboratory manual of recombinant DNA technology was developed to understand concepts of genetic engineering. The laboratory manual consisted of contents including basic microbial technology to manupulation of DNA. Using developed laboratory manual, it was applied to biology teacher of secondary school, Through activities of many experiments, they showed significant increase in understanding of concepts(p=0.000). Teachers agreeded with the need of experiments of recombinant DNA technology in science high school, However, comparing to scientifically gifted high school students biology, teachers were lower in achievement and interests about experimental activity. It suggests that teacher group need enough explanations and experimental time to understand concepts of recombinant DNA technology.