This study presents a comparative analysis of wind observations between a Doppler weather radar and a wind lidar. By integrating high-resolution vertical profiles of horizontal/vertical wind speeds and directions from the wind lidar, the radial velocities of the wind profiles relative to the Doppler weather radar are derived, and the consistency of these velocities with radial velocities from nighttime clear-air echoes observed by the weather radar is analyzed. This method was applied to evaluate the May 2023 data from the CINRAD/SA Doppler weather radar and a co-located wind lidar in Daxing, Beijing. The results indicate that there is a mean radial velocity difference of 0.37 m·s-1 between the two systems with a monthly standard deviation of 3.66 m·s-1. Daily assessments suggest that the average differences of radial velocities in 23 days between the two systems are within ±1 m·s-1, while their standard deviations in 25 days are below 4 m·s-1. The analysis demonstrates that the radial velocity of weather radar can be analyzed day by day and month by month based on wind lidar data combined with weather radar clear-air echo, supporting early detection of biases caused by equipment malfunctions or inadequate maintenance. Furthermore, the results confirm that the clear-air echo of weather radar is mainly generated by meteorological factors, and the radial velocity of clear-air echo of weather radar at night can represent the atmospheric wind field velocity. The nighttime clear-air echoes observed by the weather radar can predominantly reflect meteorological characteristics, with their radial velocities accurately representing atmospheric wind field.