The long persistence phosphor of Mg

3

Bo

3

F

3

:Mn

2+

doped with rare earth ions R

3+

(Eu

3+

Sm

3+

and Dy

3+

)was synthesized by solid-state reaction at 1100℃. The optimum concentrations ot R

3+

for preparating samples were examined. The cathodoluminescence propertiers of the longer persistence (τ=210ms) phosphors Mg

3

Eo

3

F

3

:Mn

2+

R

3+

were investigated.It is found that Eu

3+

and Sm

3+

ions affect the emission spectrum and color coordinates of Mg

3

Bo

3

F

3

:Mn

2+

phosphor. The narrow emissions ot Eu

3+

and Sm

3+

ions overlap on a broad emission band of Mn

2+

ion in these phosphors. From Fig.3 and Fig.4 it can be seen that the narrow emissions of Eu

3+

and Sm

3+

ions in Mg

3

Bo

3

F

3

:Mn

2+

are located at 613nm corresponding to

5

D

0

-

7

F

2

transition of Eu

3+

and at 651nm of Sm

3+

4

G

5/2

-

6

H

9/2

transition respectively.The brightness of red Mg

3

Bo

3

F

3

Mn

R

3+

phosphors depends linearly on the acceleration voltage.