LaCl3:Ce is an excellent rare earth halide scintillation crystal discovered in the beginning of this century. Pure LaCl3 crystal and LaCl3 crystal doped with several different Ce concentrations were grown by vertical Bridgman method. Their transmission and luminescence as well as decay time were measured and compared with each other. It was found that the cut-off edge, emission wavelength as well as decay time for pure LaCl3 crystals are respectively 215 nm, 405 nm and 1 s. This emission is explained by the self trapped exciton (STE) of LaCl3. However, with the increase of Ce concentration in the crystal, the cut-off edge of LaCl3:Ce crystal shifts to about 300 nm, and the luminescence is dominated by the emission originating from 5d-4f transition of Ce ions. Meanwhile, the increase of the luminescence intensity of Ce3+ ion emission is accompanied with the expense of STE emission, this anti-correlation between the Ce3+ and STE luminescence intensity is interpreted by the energy transfer from STE to Ce ions in LaCl3:Ce scintillation crystals.