To improve the tropical MJO simulations in Seoul National University Atmospheric General Circulation Model, both the parameterization of precipitation rate and cloud liquid water and cumulus entrainment constraint in modified Arakawa-Schubert scheme are regulated. The simple slab mixed-layer model also coupled with AGCM to consider the local air-sea interaction effect over the tropics. On the basis of the characteristics of observed precipitation, the autoconversion time scale as functin of latitude of cloud liquid water associated with the precipitation rate are adjusted and tested for Sep1996 ~ Aug 1998 period. The adjustment of minimum entrainment rate condition dependent on PBL depth improves the MJO simulation over the tropics by controlling the conditional deep convection (Tokioka et al. 1988). The simple mixed-layer model coupled with AGCM over the tropics intensifies the amplitude and seasonality of MJO activity by adding the local air-sea interaction in the direction of similarity to the observed feature. In addition to the better simulation of tropical MJO activity, the more realistic climate simulation also considered for the focus on the boreal summer season.