The phosphors

M

MgF

4

(

M

=Ca

Sr

Ba) doped with europium ions were synthesized by solid state reaction in Ar stream.Rare earth ions Eu

3+

doped in

M

MgF

4

should randomly replace the sites of

M

2+

and form defects.Its extra one positive charge may be compensated by different negatively charged defects.The charge compensation defects would influcence the local environment of the doped rare earth ions

modifying their site symmetry

and therefore different types of luminescence centers should be formed.The luminescence centers and symmetry of Eu

3+

ions in

M

MgF

4

have been investigated by fluorescence spectroscopy.There might exist three types of luminescence centers.The relation between valency of the europium and the eompositions of matrixes is discussed.The data of ESR spectra indicate that radial of the compositional canons affect the valency of europium ions.