X-ray digital imaging testing technology is a new method of nondestructive testing. Non-film real time digital radiography

which has high efficiency and low cost

especially the characteristics of digital image exchangeability and storage convenience

has become the development direction. The commonly used system consisting of a X-ray image intensifier

a video camera

an image acquisition card and a computer has the disadvantage of low imaging quality and only being used at low X -ray energy. By repetitive investigating and testing

a high spatial resolution and high contrast sensitivity system based on crystal scintillation and scientific CCD camera has been developed

which can be used both at low energy and high energy. This paper introduces the constitution of the system

including the scientific grade CCD camera which must be refrigerated

an output signal pre-processing circuit of CCD

A/D circuit

and quick data acquisition circuits using the EPP mode of computer and softwares. An aluminium casting (150mm) image obtained by the system at accelerator high energy X-ray is offered.The experimental results show the system has merits of adapting a wider X-ray energy range and imaging quality better than the system based on an image intensifier and a video camera(imaging time longer than the latter). The spatial resolution of the system is over 3lp/mm

the contrast sensitivity

when the thickness of the object to be inspected exceeds 50mm equivaled steel thickness

is below 1%.