When a high frequency alternating current flows through the Co-based amorphous ribbon bended, there is obvious stress-impedance effect due to the stress. A Co-based amorphous ribbon Co66.3Fe3.7Si12B18 annealed with an appropriate pulse current is used in the experiment. The impedance ratio dependence on the bend and the effect of alternating current value and frequency on the stress-impedance of Co-based amorphous ribbon have been studied. The experiment results show that the Co-based amorphous ribbon has obvious stress-impedance effect, and the maximal impedance ratio can reach 25%. The ribbon has negative impedance ratio when the displacement of the end of the elastomer is positive direction, however, it has positive impedance ratio when the displacement is negative direction, but they all increase with the increasing of displacement. The impedance ratio increases firstly until a maximum and then reduces with the increase of frequency at the same displacement. The impedance ratio dependence on the current value also has the same trend.