In order to study the impact of road occupation construction events on the capacity of regional road network, based on the theory of bilevel programming, a calculation model of regional road network capacity considering the capacity constraints of road sections is constructed, and the solution algorithm is designed. Through VISSIM simulation software, the capacity benchmark value of the construction section is determined, the quantitative relationship between possible capacity and various influencing factors is analyzed, and the calculation method of possible capacity under the road occupation construction condition is given. Combined with the traffic flow distribution results, the boundary value, and the change rate of road network efficiency before and after deliberate destruction, the identification method of key sections in the occupied road construction period is given. Finally, taking the urban road network in Acheng District of Harbin City as a case, the travel demand distribution is obtained through the acquisition of mobile phone signaling data, the road network capacity before and after the road occupation construction is calculated, and the importance of the road network in Acheng District during the road occupation construction period is ranked. The research shows that the capacity of regional road network is 38 445 pcu/h under initial conditions and 36 865 pcu/h during construction, which reduces capacity of road network by 4.1%.