研究了回旋管单阳极磁控注入环形电子注电子枪的设计计算原理。并以8 mm三次谐波永磁包装回旋振荡管电子枪为例，利用自编的程序进行数值计算和优化。讨论了空间电荷的影响和速度零散的改善，得到最佳的电极和电子注参数。电子枪已经应用于8 mm三次谐波永磁包装回旋振荡管研制中。得到了良好的效果。关 键 词 回旋管; 电子注; 电子枪; 数值计算Abstract The design and calculation elements of the single anode magnetron injection gun for gyrotron is researched. with 8 mm and the third-harmoric gyrotron of the casing by the permanent magnet for examples. The Numerical calculation and optimization is carried out by use of an self-redact electron trajectory code, The space charge effects and the velocity spreads is discussed. Lastly, The optimal parameters with electrode shapes and electronic trajectory was obtained. The single anode magnetron injection gun was employed experiments and researches for 8 mm and the third-harmoric gyrotron of the casing by the permanent magnet . The results was all right.Key words gyrotron; electron bunchl; electron gun; numerical calculation