A crystal growing system having multiple rotatable crucibles and using a temperature gradient method comprises a crystal furnace, a plurality of crucibles, a supporting device, and a temperature control device. The crystal furnace includes a furnace body, a heater, and a hearth, wherein the furnace body from outer to inner includes an outer shell, a fiber insulation layer, an insulation brick layer, and a refractory layer. The crucible supporting device includes an elevator, a plurality of crucible guiding tubes, and a plurality of tube holders each capable of supporting a crucible guiding tube, a moving device that is connected to the elevator, a motor with electrical power that is connected to the moving device, wherein there is an affixing device between each pair of guiding tube and guiding tube holder. Each crucible is located in a corresponding crucible guiding tube. The crucible supporting device is a rotatable device. The refractory layer is ⅔-⅚ of the total height of the hearth, and the heater, is located at ¼-½ of the height of the hearth. The present invention promotes doping of crystal and makes doping more uniform.