设计了一款长度为265 mm的飞秒条纹管。采用短磁聚焦透镜和行波偏转板，并将行波偏转板置于磁透镜之前以提高偏转灵敏度。采用蒙特卡罗方法对阴极表面理想点和阴极狭缝发射的光电子初始参量进行了模拟抽样，用CST软件的Particle Tracking模块模拟跟踪了光电子的运行轨迹，统计分析了光电子在最佳像面上的位置分布和渡越时间，给出了光电子在最佳像面上的点扩展函数和调制传递函数。计算结果显示，所设计的条纹管阴极有效尺寸达到6 mm，放大率为2.4~2.5，动态空间分辨力大于55 lp/mm。经保守估算，条纹管的时间分辨力有望达到245 fs。

A 265 mm long magnetic focusing femtosecond streak tube with a prepositive traveling wave deflector was theoretically designed. The initial parameters of the electrons emitted both from an ideal point and a slit on the surface of the photoelectric cathode were sampled with Monte Carlo method. The trajectory of the electrons were followed in the CST particle studio, after which the distribution of the electrons on the best image plane and the transit time of the electrons were statistically analyzed. To evaluate the characteristics of the streak tube, this paper also calculated the modulation transform function. The results show that the diameter of the effective area on the photoelectric cathode reaches up to 6 mm, while the amplification rate turns to be 2.4~2.5. By conservative estimates, the time resolution is expected to reach 245 fs.