This paper reports the crystal structure

characteristics of cathodoluminescence and photoluminescence of the Y

2

O

3

: Eu phosphor with the spherical and superfine particles(120~250 nm)produced by urea-sol process for the first time.The relative intensity of this kind of superfine Y

2

O

3

: Eu phosphor under 254 nm excitation is lower than that of the commercial sample with micrometer size of 6 m. But under the excitation of the electron beam with the middle accelerating voltage(~10kV) the cathodoluminescent intensties of the superfine Y

2

O

3

: Eu particles are higher than that of the commercial Y

2

O

3

: Eu phosphor. The experimental results are discussed. It is considered that the back scattering for UV photons and electrons and the surface effect in the superfine Y

2

O

3

: Eu particles in which the specific surface area(cm

2

/g) is larger and the surface atoms are in a higher energy state than the interior atoms are important.