The crosssection shape of urban opencut tunnel with large crosssection has a significant effect on the structural internal force, construction scheme and project cost. The crosssection shapes probably used in tunnel on Qunan Road in Zhengzhou are studied based on the statistics and analysis of the crosssection shapes of urban opencut large crosssection tunnel which have been constructed. The characteristics of stress and crosssection of 3 crosssection shapes of straight wall flat plate, straight wall circle plate and straight wall skew plate are analyzed. The parameters, i. e. deflection angle, skew plate span and structural dead weight, which affect the internal force of crosssection in straight wall and skew plate shape, are analyzed by loadstructure model. The study results show that: the utilization rate of crosssection and the structure stressing conditions of tunnel on Qunan Road can be improved by using crosssection in straight wall skew plate shape; and the calculation results of internal force will be affected by deflection angle, skew plate span and structural dead weight.