Non-thermal plasma is very promising in the CO

2

conversion application and it has become a worldwide research hotspot. However

the discharge in CO

2

always transits into arc or filament mode when microwave or dielectric barrier discharge is adopted. It is difficult to regulate the electrical parameters of discharge

which limits the in-depth study of the conversion mechanism. We proposed a method to obtain a uniform CO

2

/He discharge with plate-to-plate bare electrodes excited by nanosecond pulsed voltage. The ignition voltage and stable discharge voltage were obtained. It was found that the stable discharge voltage became higher when the CO

2

proportion was high

er or the pulse repetition frequency（PRF） was lower. The discharge stability were investigated under different conditions using discharge images and optical emission spectra. Stable discharge exhibited glow discharge mode during the dominant discharge

followed by multiple afterglows similar to the Townsend discharge. Furthermore

spectral line intensity ratio r（O

2

/He） and the relative intensity of CO band CO（B

1

∑→A

1

∏） are analyzed respectively. The discharge has shown memory effect in repetitive nanosecond pulsed discharge.