The instantaneous maximum torque of twin roll caster for lead blank production reaches 240kN·m.The spindle’s diameter can not be designed too big because of the limit of the size of the spindl e’s structure.So it can bring some serious problems such as flutter and torsion of the spindle.Based on the spindle’s diameter of twin roll caster as design variables and the spindle’s quality and reliability as optimization target

by using phototropism mechanism of plant growth

combined with the design mechanism of continuous casting machine’s spindle structure

the mathematical model was established.Using the mathematical model

the optimization design of spindle was carried out.The application verifies that the method is feasible

scientific and practical.