X-ray to light convertor in a real time radiography image formation system plays an important role. A new type Tb3+ doped silicate luminescent glass has been developed recently. There is no visible light dispersion in the glass and it can take the place of traditional rare earth fluorescent screen in high energy radiography applications. For its spatial resolution will not be greatly reduced when its thickness increases in a certain range, a thicker glass can be used to reach a higher DQE. The luminescent glass can be used in a radiography image formation system which adopts a high energy X-ray source up to 30 MeV. The spatial resolution is about the same as 301 type luminescent glass excitated by 100 keV X-ray and the spatial resolution may not be less than 1.5 lp/mm when excitated by 12