Abstract: The voltage-gated K⁺channels dynamical indices，resting membrane potential and potassium currents of bronchial smooth muscle cells(BSMC) were investigated by cell patch clamp technique. The experimental BSMCs of dogs were divided into control group,CD group,Tetramethylpyazine group,Baicalin group,Astraglus membranaceus group and Berberine group. The results indicated that the activation of Kv channel from CD group was significantly inhibited. This inhibitation was counteracted by Tetramethylpyazine, Baicalin and Astraglus membranaceus, which made the Kv channel of BSMC open. The most powerful one of four Chinese herbal medicinal ingredients was Baicalin. Baicalin increased the activation of the Kv channel of BSMC from CD dogs significantly and extended bronchial smooth muscle cells.