The Madden Julian Oscillation (MJO) represents the most significant form of atmospheric variability in the tropics on intraseasonal timescales. Theoretical understandings of the MJO pass through the courses of complete internal process to atmosphere (Wave CISK), the atmospheric process influenced by ocean(WISHE theory) and the most recent coupled atmosphere ocean process(WCMC model). The current atmospheric models are able to capture some of the salient features of MJO while the overall results are not satisfied. The introduction of oceanic feedback to atmospheric model by using of a simplified upper ocean model, however, can improve the MJO simulation in respects to both the strength and the propagation. An accurate representing to MJO can only be available by the using of coupled model.