The forging process of crankshaft was simulated on Gleeble 2000 thermal simulation tester. Using double-factor linear regression and single-factor second\|degree polynomial regression, the effect of heating temperature and cooling speed on the number of ferrite grain, average diameter of ferrite grain and volume percentage of ferrite was analyzed. The results show that the heating temperature and cooling speed are the main influencing factors of forging microstructure. When heating temperature and cooling speed are given, the sulfide composition change, the precipitate of carbide or nitride of V and Ti are the main influencing factors. Consequently, the effect on mechanical properties of crankshaft was discussed.