Abstract: 35-year data are used to study the statistical characteristics in intensity change of tropical cyclone (TC) over Northwestern Pacific,such as inter-decadal variation,inter-annual variation,inter-monthly variation,daily variation and regional distribution,etc.Main results are as follows:(1) Average T C deepening rate is 4.97 hPa/6h and the standard deviation is 4.54 hPa/6 h.Average T C filling rate is 5.15 hPa/6 h and the standard deviation is 4.17hP a/6h.(2) The range of T C intensity change is smallest in mid-and late-1960s and be-comes larger in 1970s and 1980s.(3) Monthly mean deepening rate is fastest in November and slowest in February.T C intensity change's range of August is the smallest among summer and autumn months.(4) T C deepens fastest at 08:00 Beijing Time and slowest at 14:00 Beijing Time.The average filling rate shows no obvious daily variation.(5) A main region w here T C deepens f ast is 12.5-20°N,132.5-150°E and the high value area of T C filling rate is around islands and continent.According to the mathematical meaning of average value and standard deviation,the stable rate,slow change and rapid change of T C intensity are defined.The inter-decadal variation,interannual variation,inter-monthly variation,daily variation and regional dist ribution of the frequency of all intensity change levels are also analyzed.Furthermore,special at tention is paid to the statistical characteristics of those sam ples which deepen rapidly around continent and islands and those which fill rapidly over sea.