Aim To observe the changes of blood pressure level and large-conductance calcium-activated potassium channels (BKCa) current in aortic vascular smooth muscle cell (VSMC) in rats after high-salt diet. Methods 3 weeks old male Wister rats were randomly divided into two groups:control group and model group, 24 rats in each group. The control group was given with normal diet (containing 0.5% NaCl), and the model group was treated with high-salt diet (containing 4% NaCl). The blood pressure in rats was measured by tail artery manometry. Whole-cell patch clamp technique was used for recording BKCa currents in rat aortic VSMC membrane. Results In the model group, the blood pressure increased significantly from the eighth week, and the blood pressure gradually increased with the prolongation of the high-salt diet time. At the tenth, twelfth, fourteenth and sixteenth week, the blood pressure in the model group was significantly higher than that in the control group (P＜0.01). The BKCa current and current density of aortic VSMC membrane in the model group increased significantly with the prolongation of the high-salt diet time. At the eighth, twelfth and sixteenth week, the peak current density of BKCa in the model group was significantly higher than that in the control group, and the difference was statistically significant (P＜0.05). Conclusion High-salt diet can lead to elevated blood pressure in rats. The BKCa current density in rats increases gradually with the increase of blood pressure due to high-salt diet.