An in-situ observation cross convective-stratiform mixed clouds in Shandong is carried out using an airborne Ka-band Precipitation cloud Radar (KPR) and DMT (Droplet Measurement Technologies) particle measurement system. The correlation is researched between the obtained KPR data, which is processed using flight track correction and data interpolation, and the liquid water content in the clouds calculated by the DMT particle measurement system. Two cloud fields are selected from the clouds of test flight and the flight are divided into 9 periods (cumulative flight of 18 min). Three of them are relatively well correlated with correlation coefficients exceeding 0.7, and the correlation formula between KPR reflectivity and the liquid water content in the clouds is fitted using the period with the maximum correlation coefficient. Based on the analysis of characteristic parameters, cloud drop size spectrum, ice crystal spectrum, and typical particle images in each period, it is found that the concentration of large cloud droplets is higher than that of small cloud droplets during strongly correlated periods, and the observed particles are mostly smaller than 100 μm; while during weakly correlated periods, the particles observed by the CIP (cloud Imaging Probe) are mostly needle-like or plate-like millimeter-sized crystals, which results in relatively big error in the calculation of liquid water content.