Abstract: In order to analyze the key parameters of the anti-rollover design of the prestressed concrete continuous box girder bridge under overload, a continuous box girder bridge is used as the background, and Midas Civil was used to establish three finite element models（considering the change in the layout of the support）, to study the variation law of anti-overturning ability of continuous box girder under 3 times overload. The analysis results show that the minimum bearing reaction force of the single-pillar pier model is much smaller than the other two models. With the increase of the support spacing, the transverse anti-overturning coefficient of the box girder increases. Changing the support spacing or changing the support type can effectively improve the force of the support. The overturning resistance and bending resistance of the small-spacing double-support model and the single-pillar pier model do not match, and the beam’s bending resistance cannot be used. The large-spacing double-support model has a close overturning overload coefficient and strength overload coefficient. The support layout of the large-spacing double support has stronger anti-overturning ability under the action of eccentric overload.