A needle-plate dielectric barrier discharge device with a transparent plate electrode is designed and used to study on characteristics of different types of discharge modes in atmospheric discharge in argon/air mixture.Three types of discharge modes,which are corona discharge,monofilament discharge,and spark discharge,are realized by changing the applied voltage.The discharge currents in positive half-cycle of the applied voltage are different from that in negative half-cycle.The optical emission spectra are collected in three types of discharges and the molecular vibrational temperatures are calculated.It shows that the vibrational temperature in corona discharge is the highest and that in monofilament discharge is larger than that in spark discharge.