Abstract: Due to its fast response, wide excitation band, low power consumption and strong reliability, plasma flow control actuators are widely used in active flow control in aerospace field. This work demonstrated a plasma flow control actuator based on three-electrode coplanar dielectric barrier discharge (TCDBD). The effects of the electrode structure on the discharge characteristics and the induced airflow velocity were investigated. In addition, the comparison of the TCDBD actuator with the surface dielectric barrier discharge(SDBD) actuator and coplanar dielectric barrier discharge (CDBD) actuator was conducted. The results show that (1) As the applied AC voltage increases, the filamentary discharge starts first between the high voltage electrode and ground electrode, and then extends to the floating third electrode. (2) With the increase of the distance between the third electrode and the high voltage electrode, the airflow velocity induced by the TCDBD actuator drops from 2.4 m/s to 0 m/s. However, the effect of the width of the third electrode on the airflow speed is negligible. (3)Under the same external conditions, the airflow velocity induced by TCDBD is lower than that by SDBD but higher than that by CDBD.