The invention discloses a method and a device for growing a germanium crystal. The method comprises the following steps of: loading a first Ge raw material into a crucible which is provided with a crystal seed mixer with crystal seeds placed therein; loading a second Ge raw material into a loading container which is to be arranged in a quartz ampoule and is used for replenishing the Ge material; sealing the crucible and the loading container in the quartz ampoule; putting the quartz ampoule sealed with the crucible and the loading container into a crystal growing melting furnace provided with a movable ampoule supporting seat which supports the quartz ampoule; melting the first Ge raw material in the crucible to generate a molten mass; melting the second Ge raw material in the container and adding the second Ge raw material into the molten mass; controlling the crystallization temperature gradient of the molten mass so that the molten mass is crystallized when contacting the crystal seeds to form a monocrystalline germanium crystal bar; and cooling the monocrystalline germanium crystal bar. The invention also provides the device which can be used for implementing the method and comprises the loading container, wherein a process for forming the monocrystalline germanium crystal bar includes bluidling 0.3-2.5DEG/cm of temperature gradient in a crystal bar growing zone.