Aiming at the problems of current intersection congestion and low utilization rate of bus lanes, this paper proposes a real-time sharing control method for dynamic bus lanes based at signal-controlled intersections. This method uses GPS to obtain real-time information on the locatin of the bus at the intersection, and obtains the number of vehicles in the bus lane through traffic detection equipment. Combined with the main signal display, the method comprehensively calculates the total delay of vehicles at the intersection before and after the bus lane sharing at the current moment. Based on the comparison results of the delay size feeding back, the lane signal shows red or green lights to tell drivers if they can enter the bus lane. This paper introduces the concept of affected vehicles, and establishes the bus lane sharing control model aiming at reducing the total vehicle delay at the intersection. Through the analysis of the two situations where the main signal showing red and green light at the current moment, this paper proposes a comprehensive calculation method for intersection delay of affected vehicles, considering the driver-occupant coefficient and the affected vehicles. The expression of the total delay difference of vehicles at the intersection before and after the bus lane sharing has been obtained. This paper numerically simulates the display of the lane signal in various scenarios to analyze the impact of factors on lane sharing, such as existing vehicles in the dedicated lane, the position of buses, and the status of the main signal display. The results demonstrate that the control method aligns well with real-world situations and effectively improves the utilization rate of the bus lane, making full use of green light time at the intersection. This method provides a new idea for synamically sharing of bus lanes and alleviating road congestion.