Aim To investigate the characteristic of chloride currents and Ca 2+ entry induced by adrenaline (Adr) in A10 vascular smooth muscle cells (VSMC). Methods Cell attached patch clamp and Fura 2 fluorescence techniques were used to observe the chloride currents and the changes in [Ca 2+ ]i. Results The open probability (Po)and mean open time(τo) of chloride channels were increased by 10 μmol/L Adr; the Po were increased from 0.061 to 0.69; the τo were increased from 1.08 ms to 6.44 ms. The activatoion of chloride channels were decreased by 10 μmol/L nifedipine and nearly completely inhibited by subsequent addition of 1.5 mmol/L EGTA. Application of Adr activated Ca 2+ influx from the extracellular space. Both of the chloride currents and Ca 2+ influx could be inhibited by the chloride channels blockers niflumic acid (NFA) in a concentration dependent manner. Conclusion The Adr can increase the activation of chloride channels in VSMC and the action is dependent on the extracelluar Ca 2+ influx. The chloride channels play an important role in the regulation of Calcium movement in VSMCs.