在常温常压的大气压条件下，采用重复频率高压纳秒陡度脉冲和线型电极产生了大面积的弥散放电等离子体。通过实验，对弥散放电及其电流特性进行了研究，分析表明，弥散放电电流由传导电流分量和位移电流分量合成而成。其特征波形为，在电压波峰附近对应着多个电流振荡尖峰，在波尾阶段传导电流分量会逐渐补偿位移电流分量，合成电流幅值很小。弥散放电向电弧或火花放电转化伴随着传导电流密度的增大，反之亦如此。长导线和大间距有利于长波尾脉冲产生均匀弥散放电等离子体。对大气压空气下弥散放电的产生机制进行了分析，高场强区引发下的大面积低场强电离可能是弥散放电形成的关键。“,”In room-temperature atmospheric air, the large-scale diffuse plasmas can be generated via high-voltage nanosecond pulses with short rise time and wire electrodes. Analysis shows that the current of diffuse discharge includes two components: conduction current and displacement current. The characteristic of current waveforms is that there are several current oscillation peaks at the time of applied pulsed voltage peak, and at the tail of applied pulse, the conduction current component will compensate the displacement one so that the measured current is relatively small. The transit from diffuse discharge to arc discharge is always with the increasing of conduction current density, and vice versa. As for nanosecond pulses with long tail, the long wire electrodes are help for generating non- equilibrium diffuse plasmas.