Tacan system adopts the question-and-answer pulse distance measurement technology to calculate the distance between the ground station and the aircraft.The traditional half-detection detection timing point is greatly affected by noise and affects the accuracy of ranging.The correlation method proposed in this paper matches and aligns the received pulse with the reference pulse, makes full use of the pulse information, extracts the bell-shaped pulse timing point, and uses the method of derivative weighting to further improve the ranging accuracy.Through simulation analysis, this method can effectively reduce the influence of coarse errors, accidental errors and random noise on the extraction precision of timing points, improve the system's ranging accuracy and anti-jamming performance, and can also evaluate the signal quality by calculating the matching coefficients.