The effects of inhibiting or activating BKCa on the proliferation, migration, and apoptosis of HBZY-1 cells, as well as the changes of TGF-β1, Smad2/3, and ECM (Col IV, FN) were observed to explore the role of BKCa in DKD and its mechanism, so as to provide new ideas for the clinical treatment and drug development of DKD. Here, SMAD2 is linked to diabetic kidney disease.