By means of finite element method software simulation analysis, using strength reduction finite element method analyse factor of safety of embankments. Nowadays most finite element program is analyzed in the perfect elasto-plastic with the Mohr-Coulomb not equiangular hexagon circumcircle Drucker-Prager yield criterion, it have margin of error with not equiangular hexagon in π-plane, so we use Mohr-Coulomb equivalent area circle D-P yield criterion instead of it. Calculate conversion coefficient of two safety factor under different yield criterion. Using safety factor through finite element software by strength reduction multiply by conversion coefficient, get new safety factor. Through the example of high embankment of old road widened in Shanghai-Chengdu expressway Hejiaping cable section K2+ 710~890, validation of this method calculated the accuracy of the safety factor, the results show that the new factor of safety closer to the true value.