Abstract: To direct extraction of ginsenoside Rg5 from ginseng fibrous root powder ( GFRP) , solve the problem of long extraction time, low extraction rate, the microwave assisted extraction technology of ginsenoside Rg5 was carried out and optimized by response surface method based on single factor experiment, the extraction power, acid concentration of extraction solvent, solid-liquid ratio, extraction time and their interactions effected on the extraction yield of ginsenoside Rg5 were investigated.The results showed that the order of influence on the extraction yield of ginsenoside Rg5 was as follows: acid concentration of extraction solvent > extraction power > solid-liquid ratio > extraction time.The optimal condition obtained from RSM was as follows: extraction power of 500 W, acid concentration of extraction solvent of 0.12 mol·L-1, solid-liquid ratio of1∶ 42 ( g·m L-1) , extraction time of 9 min, the extraction yild of ginsenoside Rg5 can reach 3.14% under the optimal condition, which indicated the method could extrat Rg5 from GFRP effectively.