[Purposes] The paper aims to address traffic congestion in the short-distance connecting section between an urban expressway off-ramp and a ground signalized intersection. [Methods] A dynamic lane setting method for short connecting sections of off-ramps was proposed. Considering the traffic characteristics of the short connecting section of the off-ramp, dynamic lane design was conducted. A dynamic lane function allocation model was constructed with the objectives of minimizing the total flow ratio of traffic flow in the short connecting section of the off-ramp and minimizing the sum of the absolute values of flow ratio differences, and with the number of lanes, lane positions, signal phases, queue lengths, and other factors as constraints. Considering both the operation time and operation benefits of the dynamic lane allocation scheme, an adaptive conversion method using pre-signals was studied for the dynamic lane allocation scheme. A case simulation analysis was conducted with the Xiangfu Road Elevated Expressway off-ramp connecting to the ground intersection of Xiangfu Road and Shaoshan Road as the research object. [Findings] After dynamic lanes are set in the short connecting section of the off-ramp, the average vehicle speed increases by 40.8%, and the average vehicle delay and average number of vehicle lane changes decrease by 21.4% and 12.6%, respectively. [Conclusions] Setting dynamic lanes can effectively improve the traffic efficiency of the short connecting section of the off-ramp and reduce traffic flow weaving in this section.