Based on the intercomparison test data from high-quality radiosonde systems organized by WMO in Yangjiang quite well, Guangdong from 12 July to 3 August 2010,the performance of Vaisala RS92 and Changfeng radiosonde on clouds vertical structure is analyzed, whose results are validated by ground-based remote sensing instruments(laser ceilometers and cloud radar) simultaneously. The measured results of these two instruments could reveal the actual cloud condition in Yangjiang, especially for the low-level clouds. While as for as the low-density cloud was concerned, both of these two kinds of radiosondes misjudged it for multi stratus; it is easy for Changfeng to miss cloud layer. These two radiosondes are also not very good at judging the high clouds. The results of the base and top height of high cloud by RS92 are higher than those by Changfeng on the average.