The yellow phosphor Ca2BO3ClEu2+ was synthesized by high temperature solid state reaction method, and the results show that the phosphor can be excited by the near-ultraviolet and blue light. Under the 460 nm excitation, the phopshor presents a single broad emission band, in which the peak appeared at 573 nm. Montoried at 573 nm, the excitation spectrum cotained 300～500 nm excitation band, and the excitation peaks located at 413 nm and 475 nm, respectively. The effect of Eu2+ concentration on the crystal structure and emission intensity was studied. And the results show that the all patterns data well agreed with the standard data. However, the emission intensity of the phosphor was influenced by the Eu2+ concentration, and the intensity reaches maximal value at 2% Eu2+. According to the Dexter theory, the concentration quenching mechanism is the d-d interaction.