Abstract: Analyzed in this paper are the 16year (1988-2003) tropical cyclone (TC) intens i ty data from three major forecast centers for Northwest Pacific typhoons, i.e. C hina Meteorological Administration (CMA), Regional Specialized Meteorological Ce nter Tokyo (RSMC Tokyo), and Joint Typhoon Warning Center (JTWC). Analysis resul ts show that the mean strength difference of tropical cyclones between the CMA a nd RSMC Tokyo datasets and between the CMA and JTWC datasets are 0.6 and 1.7m/ s, respectively, which are both significant at the 1% confidence level; the maximu m difference in the strength of the same tropical cyclone determined by three ma jor typhoon forecast centers is more than 30 m/s; and the number of typhoons of the CMA dataset is greater than those of the RSMC Tokyo and JTWC datasets, and the mean square deviation of the annual frequency of typhoons of the CMA datasets is also largest, but there is no significant difference in the frequency of var ious category tropical cyclones among the three center datasets. The comparison of the data of different time periods with and without flight reconnaissance sug gests that the flight reconnaissance over TC can to some extent reduce the discr epancy in determining the strength of TC among different centers.