Abstract: In this paper,the PSU/NACR MM4 model are employed to investigate the prerequisite conditions to a explosive cyclone which happened in June 1-2 1993 at Yellow Sea.Several smoothing testare conducted and the result shows that the merge of the troughs associated with the northern cold airand the southern moistjet,the strong low-level moisture transport channel are two indispensable factors to the explosivecy clone development which happens in China's eastern coastal area in early summer.