介绍了天鹅绒阴极二极管的结构及天鹅绒阴极的设计 ,给出了二极管参数的测量方法及结果。对 3种不同材料的天鹅绒阴极进行了实验研究 ,获得了大面积均匀电子束 ,并对电子束的横向及径向均匀性进行了诊断。实验结果表明 :二极管工作状态接近的条件下 ,3种材料的天鹅绒阴极所获得的大面积电子束均匀性相近 ,而与天鹅绒的材料基本无关 The structure of the velvet cathode diode and the design of the velvet cathode are introduced. The measuring methods and the results of the diode parameters are given. The velvet cathodes of three different materials were studied experimentally, a large area of ​​uniform electron beam was obtained, and the transverse and radial uniformity of the electron beam was diagnosed. The experimental results show that the uniformity of large-area electron beam obtained by the velvet cathodes of the three materials is similar to that of the velvet materials