Abstract: By failure analysis on crankshaft made of nodular cast iron,depending on the statistics and combining with the actual site condition,it is believed that increasing the toughness of material and intensifying fillet radius are the major measures to prevent from failure of crankshaft. The fillet radius is made by means of rotary rolling,which is an effective process. Improvement of hot process-graining graphite in cast and optimizing isothermal hardening in heat treatment can be mainly adopted.