The invention is a doped lutetium disilicate submicron imaging fluorescent screen and its preparing method, adopting a heating-resistance liquid phase epitaxy (LPE) furnace to grow a doped lutetium disilicate flicker film on a lutetium disilicate substrate to make it, and its structure expression is (CexMzReyLu1-x-y)2Si2O7 / (Lu1-yRe)Si2O7, where 0.001<=x<=0.01, 0 <=y<=0.3, 0.001<=z<=0.01, Re stands for one or multiple of Sc, Er, La, Ho, Dy, Yb, Yt, Gd, In, etc, and M stands for Eu or Tb. It can be widely applied to the ray detection fields such as scientific research, medical treatment, industrial nondestructive detection, geological exploration, security inspection, national defence, etc.