The invention discloses a luminescent material doped with niobate, tantalate and the mischcrystal thereof, and a crystal growth method thereof for the melt process. The molecular formula of the compound is (RExRE'y) M1-x-y-z-deltaM'z (Ta1-u+delta' Nbu+delta') O4+delta (x equals to 0 to 0.5, y equals to 0 to 0.5, 0 is smaller than x+y and x+y is smaller than and equal to 0.5, z equals to 0 to 0.5, delta equals to -0.4 to 0.4, and delta'+delta' equals to delta), wherein, the RE and the RE' are Yb, Nd, Er, Tm, Ho, Ce, Pr, Eu, Bi, Ti and Cr, and the M and the M' are Sc, Y, Gd and Lu. The well prepared raw material becomes the starting material of crystal growth after uniformly mixing, pressing molding and high temperature sintering; the starting material for crystal growth is put into a crucible and sufficiently heated and fused to form an initial melt for melt process growth, and then the melt methods can be used for crystal growth such as a Czochralski method, a Bridgman-Stockbarge method, a TGT method and other melt methods; and the (RExRE'y) M1-x-y-z-deltaM'z (Ta1-u+delta' Nbu+delta') O4+delta can be used as the detection material for the working laser material, the high-energy rays, the high-energy particle, and the like.