The preparation and the luminescent properties of green-emitting phosphor Ca3SiO5:Eu2+ have been studied. The broad green emission band with the peak located at 502 nm which consists of a main and a subsidiary emission peak at 501nm and 570nm，respectively， originate from the centers of Eu2+ ions. There are two different Eu2+ emitting centers in Ca3SiO5:Eu2+, which has been confirmed by the experiment results and empirical formula of Van Uitert，and the Eu2+ ions occupy Ca2+ sites with coordination number 8 and 4 in this phase. The excitation spectra extend from 250 nm to 450 nm and the excitation peak positions are located around 375 nm. The phosphor can be excited effectively by InGaN chip emitting in the range of 350—410 nm.