Abstract: Objective To explore the influence of macrophage migration inhibitory factor (MIF)on signal transmit route of collagen synthesis in vascular smooth muscle cell (SMC).Methods The expression of signal transmit phosphorylated ERK of SMC in the rat aorta was measured by the western blotting procession after stimulation by MIF,Ang Ⅱ,MIF +PD 98059,AngⅡ +PD 98059. Results The expression of phosphate ERK of the SMC raised significantly after MIF and Ang Ⅱ stim-ulation (P <0.05).The mount of phosphorylated ERK in the Ang Ⅱ group was higher than that in the MIF group.After adding PD 98059,the phosphorylated ERK in both groups decreased significantly (P <0.05).Conclusion Both MIF and Ang II can activate MAPK/ERK route,and it might act in the same signal transmit route of collagen synthesis between MIF effect and Ang II effect.