The invention discloses a polysilicon 
ingot casting device and 
ingot casting method. The 
ingot casting device disclosed by the invention comprises a 
crucible containing a 
silicon material. The 
ingot casting device is characterized by also comprising a gas delivery 
pipe and a 
power unit, wherein the gas delivery 
pipe is used for delivering 
argon gas to 
silicon liquid obtained by melting the 
silicon material; the 
power unit is used for driving the gas outlet end of the gas delivery 
pipe to 
charge and discharge the silicon liquid; the gas inlet end of the gas delivery pipe is arranged outside the 
crucible; and the 
power output end of the 
power unit is fixedly connected with the gas outlet end of the gas delivery pipe. The 
argon gas introduced into the silicon liquid can accelerate the separation of impurities in the silicon liquid from the silicon liquid, so that the impurities contained in the silicon material are quickly separated from the silicon liquid in the 
molecular motion process and reach to the silicon liquid surface to be volatilized so as to carry the impurities in the silicon liquid away, thereby increasing the 
impurity volatilization amount, reducing the 
impurity content in the silicon ingot, and enhancing the quality of the silicon ingot. Meanwhile, the delivery of the 
argon gas into the silicon liquid is carried out after melting the silicon material into the silicon liquid, and is finished before the silicon 
liquid crystal growth process; and the process can not prolong the existing 
ingot casting time or influence the existing 
ingot casting procedure, and thus, is convenient to implement.