Objective To investigate the dynamic expression profile of KCNQ1 channel in rat developing pancreas and adult rat islets, so as to provide experimental basis for further analyzing the possible role of KCNQ1 channel in β-cell development and function. Methods The gene expression patterns of embryonic day 12.5 (E12.5), E15.5, E18.5, new-born and adult rat pancreas were compared using the GeneChipRAE 230A. The expressions of KCNQ1 channel subunits in rat pancreas at the above five stages and adult rat islets were also detected and analzyed by RT-PCR. Results The results of genechip showed that the expression of transcription factors related to endocrine cell differention and maturation peaked at E15.5 and E18.5, respectively. The expression of mature β-cell specific genes increased significantly at E18.5, but KCNQ1 and KCNE1 only started to express at E18.5. The results of RT-PCR showed expression of multiple KCNQ1 channel subunits in adult rat pancreas and islet. Conclusion The expression of KCNQ1 channel appears in the later stage of pancreatic development when the endocrine cells undergo further maturation, and has a higher level in adult islets. The expression profile of KCNQ1 channel subunits indicates that KCNQ1 channel might be expressed in mature β-cell and involved in its endocrine function.