On the basis of the brief review of the characteristics of atmospheric intraseasonal oscillation(MJO), its linkage between the tropical and mid-high latitudes and its interaction between Northern and Southern Hemispheres, the progress of the investigation on MJO is substantially summarized, involving the relationship between MJO and El Nino,MJO’s dynamical mechanism,its seasonal variation and interannual anomaly,with the problems in MJO study and prospects in this area discussed briefly.