Based on the characteristics of simultaneous observation of cloud tops by ground-based millimeter-wave cloud radar and FY-4A satellite, the relationship between cloud top height observed by cloud radar and AGRI load channel data of FY-4A satellite is analyzed, and a joint retrieving method of cloud top height based on cloud radar and FY-4A satellite is proposed. The cloud top height of the satellite in an area around the installation point of the cloud radar is retrieved, and the retrieval results are verified and analyzed. The results show that the 11-14 channel values of FY-4A satellite are linearly correlated to the cloud top height of cloud radar. Moreover, the ratio of FY-4A satellite channel values to cloud top height observed by cloud radar shows the seasonal characteristics of minimum in winter, followed by spring and autumn, and maximum in summer. The correlation coefficient between cloud top height obtained from satellite-ground fusion inversion and cloud top height measured by cloud radar is 0.84, and the root-mean-square error is reduced by 0.7 km after fusion, which improves the inversion accuracy of satellite cloud top height.