In order to analyze the optimization problem of bus route departure time, two intersecting bus routes with transfers were taken as the research object. Taking into account passenger congestion, a bus timetable optimization model was constructed with the objective function of minimizing the total waiting time, transfer waiting time, and non transfer passenger waiting time. Two city bus routes in Hohhot City, namely Line 4 "JINYU Global Center to Affiliated Hospital of Medical University" section and Line 78 "Hohhot Bus to Saihan District Education Bureau" section, were studied, and the optimization model was solved using genetic algorithm. The results show that the proposed city bus timetable optimization scheme can shorten the transit waiting time and total waiting time by 18.1% and 10.7% respectively, thereby validating the proposed optimization model's effectiveness in improving the operating efficiency of intersecting routes.