Objective To construct Cchl1a3 gene R528H knock-in mouse model related to hypokalemic periodic paralysis.Methods ES cells were transfected with Cchl1a3-Konckin targeting vector linearized by Not I digestion , selected in the medium containing both G 418 and ganciclovoir .Resistant clones were screened by PCR and further confirmed by DNA sequencing for correct homologous recombinants .Chimera mice were obtained by routing microinjection of homologous recombined ES cells into blastocysts .Heterozygous mice were obtained by mating .Through heterozygous mice with FLP mice mating , removal of neo gene heterozygous mice were established and identified with the PCR and DNA sequencing . After mating, homozygous offspring were constructed and observed .Results ES cells were successfully transfected withtargeting vector .It was confirmed that 9 resistant clones happened right homologous recombination by PCR and DNA sequencing .7 chimera mice were obtained by microinjection .After breeding the chimeric mice , heterozygous mice were mated FLP mice to obtain 9 heterozygous mice removal of neo gene, the finally obtained 15 homozygous mice with Flp-deleted neo gene.In the developmental stage of sexual maturity , the spirit of the mice, restaurants and activities in good condition, but the gradual emergence of hair removal at 4 months of age, skin ulceration and even death .Conclusions We successfully constructed Cchl1a3 gene R528H mutation homozygous mice.And it laid a foundation for the study of human CACNA1S gene function and to clarify the molecular mechanism of hypokalemic periodic paralysis .