Abstract: The electron beam ion trap(EBIT) and the electron ion source(EBIS) are new instruments for the study of X-ray produced by very highly-charged ions when they interact with free electrons. Some of the design and physics features of EBIT/EBIS are described, and the characters of the X-ray produced with them are described too. Micro-focal X-ray can be taken out if focusing the ion beam with the ion-optical system.