The height of the cloud base has significant effects on the global radiation balance and the aviation. In allusion to the merit and demerit of active and passive observations, a technique of spreading cloudbase height from CloudSat, using the MODIS classification, is advanced. Firstly, based on MODIS and CloudSat data, the method (CSAT) using satellite classification to extend the CloudSat data is compared with a traditional distanceweighted approach (MSAT) using regression analysis method. Then, the uniformity of cloud base over China and its neighborhood is analyzed. Eventually, using the statistic features of cloud base heights for different cloud types from CloudSat, a method combining the MODIS classification with distanceweighted to estimate cloudbase height is established and validated. The result indicates that the standard deviations of cloudbase height errors for all MODIS cloud types are totally less than 1.5 km, and the average values are also less than 1.5 km for all MODIS cloud types except cumulonimbus, of which the mean in the case of the distance between observed and predicted sites being greater than 400 km is slightly greater than 1.5 km.