Abstract: In order to obtain the vertical microphysical structure of the stratiform cloud and characteristics of the radar parameters and reveal the precipitation mechanism, the airborne Ka-band cloud radar and DMT particle measurement system are used to target the stable precipitation layer of a cold front in Shandong Province on 17 November 2019. The results show that the observed cloud layer consists of two parts: Altostratus (As, 3100-4500 m) and nimbostratus (Ns, 800-2600 m). The content of As supercooled water is low, with an average value of 0.0026 g·m^-3 and the maximum value of 0.008 g·m^-3. The average ice crystal content in the cloud is 8.2 L^-1. In the vertical space, the ice crystal size and spectral are different. Ice crystals grow through deposition, with a maximum diameter of 900 μm. In the state of equilibrium spectrum, the ice concentration has a good correlation with radar reflectivity, and the maximum correlation coefficient is 0.84. The movement of particles in the cloud is different. The speed of small particles varies greatly and is easily affected by updrafts. The falling speed of large-scale ice crystals is stable. The central part of the Ns (1750-2150 m) is rich in supercooled water, with the maximum content of 0.354 g·m^-3. The average radar reflectivity of the supercooled water region is 7.48 dBZ, the Doppler velocity is -2.3 m·s^-1, and the velocity spectral width is 0.7 m·s^-1. The height of the supercooled water layer in the cloud can be comprehensively judged by combining a variety of detection data and parameters. The upper part of the Ns is dominated by ice crystals and the lower part is filled by melted particles in the warm zone. The average concentration of ice crystals is 208 L^-1, which increases through the riming process, and the maximum diameter is 450 μm. The radar reflectivity profile increases as the height decreases from 2200 m to 1500 m, remains unchanged from 1500 m to 1200 m, and decreases below 1200 m. There is no obvious bright band at 0℃ level, and the velocity spectral width profile increases as the height decreases. The supercooled water in the stratiform cloud in early winter is abundant, and the concentration of ice crystals meets the standard of seeding area, which has a certain potential for rainfall enhancement.