Abstract: Microstructures around the interface in 321/Qd370qD explosive welded plate were analyzed by transmission electron microscopy(TEM). The results showed that there are a lot of amorphous phases and nanocrystals near the interface,and in the plate,some distance from the interface,also exist a large number of nanocrystals. There were spinodal decomposition structures in the plate. The sheet twin martensite and face- centered cubic M₂₃C₆ were found in the front swirl.