The invention relates to the field of radiation materials, in particular to orthosilicate fluorescent powder. Part of O<-2> in a silanoxide tetrahedron is replaced, the orthosilicate fluorescent powder has a P2nn crystal structure and gives off green radiation under the strong shortwave radiation excitation of InGaN heterojunction, wherein the maximum spectrum depends on the interrelation between the amount of Me<+2> or Ln<+2, 3> in a cation crystal lattice, and the intensity is determined by the amount of the atom O<-2> in the component which is replaced in the V, the VI and the VII families and is taken from the series of F, Cl, Br, I, S, Se, N and P. The orthosilicate fluorescent powder has two excitation wave zones of which the range is between 360 and 400 nanometers and between 450 and 490 nanometers, and the materials are used for establishing a bright and effective green LED by using a nitride heterojunction as a substrate.