Based on the structure of forward converter, a real-time adaptive (RTA) leading edge blanking (LEB) circuit was designed. By blanking oscillation time and oscillation amplitude, the optimal blanking time was tracked to realize RTA LEB, which reduced the system size and cost, and the high-frequency development of the circuit was not limited. The output current information without spike oscillation could be obtained by the designed LEB circuit to ensure that the system could respond quickly to the output load change. The circuit was designed in a 0.18 μm BCD process. Simulation results show that the start-up overshoot was only 50 mV without other additional current limiting functions, and the undershoot voltage and overshoot voltage were 519 mV and 578 mV respectively during load steps.