Abstract: Taking TC4 titanium alloy specimens as research objects, the relationship between digital radiographic parameters (exposure, magnification, distance from X-ray Source to the flat panel detector) and signal-to-noise ratio (SNR) and spatial resolution of DR image was studied. The experimental results show that the SNR of DR image increases with enhanced exposure while no significant correlation is observable between spatial resolution and exposure (Tube voltage: 90 kV; Tube current: 2.0~8.5 mA).When the tube current is fixed at 7 mA and the magnification is increased from 1.0 to 5.0, the spatial resolution is directly proportional to the magnification, while SNR presents a trend that first increases sharply and then strengthens slowly within the magnification range from 1.0 to 3.5. Until the magnification is higher than 3.5, SNR tends to be constant. When the magnification is maintained at 2 both the image spatial resolution and SNR are directly proportional to the distance (100~180 cm) from the source to the detector. Taken as a whole, high image spatial resolution and SNR of TC4 titanium alloy can be obtained by setting suitable parameters including high exposure, large distance from the X-ray source to the flat detector, and appropriate magnification.