Based on the monthly seawater temperature and salinity from the World Ocean Atlas 2013 and the sea surface wind from the National Centers for Environmental Prediction reanalysis data, the spatial distribution of the North Pacific Tropical Water (NPTW) and Intermediate Water (NPIW) east of Taiwan are studied using a similarity coefficient method. We also discuss the mechanism underlying the seasonal variation in the NPTW and NPIW. The climatological results show that the NPTW east of Taiwan is mainly located at 25–300 m depth, with a volume of 6.76 × 10¹³ m³. It is larger in winter and smaller in autumn, which is mainly modulated by monsoon and the Kuroshio. The NPIW is generally located at 400–1100 m depth, with a volume of 1.39 × 10¹⁴ m³, which is more than twice that of the NPTW. It is larger in summer and smaller in winter, which is mainly affected by mesoscale eddies and the Kuroshio.