Whether or not reasonably to select the grounding ramp position of urban interchange will seriously affect the traffic effect of ramp and even interchange. Aiming at this problem, combined with an engineering case of setting the grounding ramp for Shizha Interchange in Kunming Ring II, the ramp positions of entrance road and exit road of intersection at grade are analyzed. How to determine the minimum distance of grounding ramp to ground intersection at grade is discussed. How to reasonably arrange the position of ramp on the cross section of road is analyzed. The setting of the ramp on the left, center and right on the cross section is discussed respectively. The obtained conclusion shows that the grounding position of grounding ramp has a great influence on the traffic effect of ramp. The on-ramp and off-ramp of grounding ramp should keep a certain distance from the ground intersection at grade. Various factors should be comprehensively analyzed to arrange the grounding ramps at the most suitable positions on the cross section of road. The traffic effect of ramp is better from the effects of engineering cases.