In the content of 1975-1995 OLR data and 1979-1995 NCEP/NCAR reanalysis data,the features of tropical convective activitie s are discussed in wet/dry summers over the mid-lower valleys of the Yangtze an d north China,with focus on the relationship between the position/LFO of ITCZ and the flood/drought over the two areas.Results show that:1)there exits a close relationship between the flood/drought over the study areas in summer and the co nvective activities over the tropical Pacific in the preceding January,with stro ng convection in eastern Pacific and weak in western Pacific corresponding to flood in the mid-lower valleys of the Yangtze and drought in north China,and v.v.;2)when ITCZ lies in the south(north) of its mean position,there will be flood(drought) over the mid-lower valleys of the Yangtze and drought(flood) over north China;3)there are differences in LFO of OLR between wet/dry summers,which is ma inly characterized by its propagation and intensity.Such a differences may serve as one of the important causes for the difference of summer rainfall between th e two areas.