the diameter 200 mm CZSi of solar cell was grown in 18 inchmulti-heat system. The simulation result based on computer shows that thissystem can decreases the temperature grads of melt silicon in vertical directionand effectively restrains the thermal convection of melt silicon. Furthermore,the system can also increases the thickness between melt silicon and crucible,decreasing the penetration of SiO, the concentration of oxygen and carbon insilicon can be reduced. The simulation result consists with the experiment re-sult well.