Abstract: The present disclosure provides a growth method of a high-temperature phase lanthanum borosilicate crystal, where the high-temperature phase lanthanum borosilicate crystal is a ?-La1-yLnyBSiO5 crystal prepared by a high-temperature flux method; a composite flux system is (La1-yLny)BO3—LiMoO4—SiO2—B2O3, and (La1-yLny)BO3, LiMoO4, SiO2, and B2O3 in the system have molar percentages of x1, x2, x3, and x4, respectively; 0<x1<0.3, 0.7?x2<1, 0<x3<0.3, x1+x2+x3=1, x1:x4=2:1 to 4:1. In the present disclosure, a difficulty is overcome in the crystal growth of ?-LaBSiO5 due to phase transition. The crystal is an optical function material that does not undergo the phase transition during annealing and can exist stably at room temperature. The crystal is widely used in laser, terahertz, and other fields.