Abstract: A PIG ion source, originally designed for positive ion generation to neutron tube, has basic limitations, such as low monatomic ion fraction, serious sputtering of the target surface and large power consumption. In order to solve these defects and improve the lifetime and stability of neutron tube, a PIG ion source was modified for negative hydrogen ions extraction. A new structure of ion source was designed for neutron tube, and experiments about beam current extraction from PIG negative hydrogen ion source were performed. The effects of magnetic field of the ion source, different cathode materials and the aperture size of extraction cathode on hydrogen ions extraction were studied, respectively. The experiment data demonstrate that the negative hydrogen ion source can be used to produce the neutron tube with the good performance.