Abstract: In order to elucidate the biological function of StmiR166b of potato（Solanum tuberosum L.），plantlets in vitro of potato cultivar‘Gannongshu 2’were used as dornors，the differential expression of StmiR166b and its target genes StHB14 and StHB15 were determined in different tissues by real-time quantitative PCR. Furthmore，the pre-structure of StmiR166b-StmiR166b* muture sequence was cloned using pRS300 plasmid as a template and over-lapping PCR technology. The artificial expression vector was constructed and further the transgenic potato plants were obtained via Agrobacterium tumefaciens- mediated method. The results showed that StmiR166b and its target genes StHB14 and StHB15 were expressed in roots，stems and leaves，which were down-regulated expression in the transgenic lines L1 and L3. The growth of the transgenic lines was inhibited，and their plant height and root length were shorter cmopared with the untransgenic plants under normal growth conditions.

Key words: potato, StmiR166b, StHB14, StHB15, expression vector