objective To generate the heart-specific KCNQ1V180L expression transgenic mice and an animal model for the study of KCNQ1 function and its effects on arrhythmia. Methods The transgenic vector was constructed by inserting the human KCNQ1V180L gene into the down stream of α-MHC promoter. The transgenic mice were created by the method of microinjection. The genotype of transgenic line was identified by PCR and the expression level of the gene was determined by Western Blot. The pathologic changes were analyzed with echocardiography and electrocardiography (ECG). Results Two lines of C57BL/6J transgenic mice with high levels of KCNQ1V180L expression were established. The heart of KCNQ1V180L transgenic mice showed thick ventricular wall, smaller ventricular chamber and increased fractionl shortening (FS%) compared with that of the non transgenic mice. Ventricular repolarization dysfunction was determined by ECG. Conclusions The KCNQ1V180L transgenic mice showed a similar phenotype with human long QT syndrome (LQTS). The transgenic mouse could be an useful animal model for the research of KCNQ1 gene function and the relationship between KCNQ1 mutation and arrhythmia.