Lutan-1 SAR satellite is the first group differential interferometric SAR satellites in China. Coherence is a key factor for the quantitative interferometric applications of SAR satellite. In order to effectively evaluate the coherence characteristics of Lutan-1 SAR satellite, coherence analysis is carried out in different application scenes for monostatic and bistatic formations. Firstly, the main factors affecting interference coherence are analyzed and discussed based on the theoretical derivation. According to the satellite and SAR configurations parameters, as well as the relevant technical indexes obtained by in-orbit test, the coherence indexes of Lutan-1 SAR satellite are analyzed from the aspects of baseline coherence, ambiguity coherence, Doppler coherence, processing coherence and volume scattering coherence. Furthermore, the coherence characteristics of Lutan-1 SAR data with bistatic formation were analyzed over typical bare land, forest and desert areas. And the coherence characteristics of repeat-track SAR data were discussed over different application scenes, including Beijing, Datong Shanxi and Liupanshui Guizhou. Based on the above analysis and discussions for Lutan-1 SAR satellite, it provides basic support for the applications of DSM/DEM construction and deformation monitoring.