[Objective] The aim is to study the construction of vectors expressing foreign protein in potato starch grains specifically, and provide some reference for solving industrialized core problem of high cost and low expression level of foreign protein. [Method] By using molecular biological techniques of RT-PCR and nested PCR, plant expression vector for the foreign protein locating in the potato starch grains was constructed. [ Result] Coding sequence （ GC20 ） of potato starch grains that was located and expressed by GBSSI promoter was cloned. Plant expression vector was screened out through connection, transformation and enzyme digestion identification. [ Conclusion] This result laid a foundation for further screening the foreign protein on the potato starch grains.
