A new method of microwave extraction was used to extract the pigment from Polygonum Cusdidotum Steb.et Zucc. The extraction processes were investigated and the optimal conditions were determined as follows: raw material 2.0000 g dry powder, the extraction agent 75% (v/v) alcohol solution, the ratio of raw material to extraction agent 1:60 (g:ml), the microwave power 464 W, and the extraction time 300 s for two times. Compared with the solvent or soxhlet extraction, microwave extraction reduced the extractio...