神龙二号注入器是一台感应叠加型强流脉冲电子束源，采用热阴极工作模式，为神龙二号加速器提供间隔可调的三脉冲电子束。该注入器的束流调试采取PIC模拟和实验调试交互验证、互相促进的方式，先是通过束斑测量确定引导线圈磁场的加载范围，然后通过PIC方法逐级梳理阳极段束线各线圈的磁场配置，再通过束斑测量加以确认。通过这种束流调试方法，获得了保持束流脉冲平顶完整通过的三种磁场配置，以适应下游加速段束流传输的不同要求。讨论了影响束流调试效果的因素，认为提升神龙二号注入器性能的关键是进一步改进大面积热阴极发射的均匀性。

The Dragon-Ⅱ injector is a strong current pulse electron beam source, it is an inductive adder with thermal cathode and provides three pulse beams with adjustable pulse interval for Dragon-Ⅱ LIA. The way with cross validation and mutual promotion of PIC simulations and experiments is adopted during the injector beam tuning. First, the magnetic field loading range of the leading solenoid is determined approximately by the beam spot measurements. Second, the magnetic field configuration of every solenoid installed in the anode beam line is simulated by PIC step by step, and then confirmed by the beam spot measurements. By this means, three kinds of magnetic field configurations which can keep the pulse flat-topped completely are obtained in order to meet the different requirements of the downstream beam transportation. Finally, the factors affecting the effects of beam tuning are discussed and the key to the injector performance improvement is considered to be further improving the emission uniformity of the large area thermal cathode.