The heat transferred through sea surface and the 900 hPa, 850 hPa and 700 hPa layers during seven cyclones formed over the Kuroshio area is calculated, and the influence of heat supply of the area on cyclones development is studied.Analyses indicate that the heat so transferred has obvious influence on the cyclones over the Kuroshio in spring and winter, and that the effect of precipitation is secondary to the East China Sea cyclones, although it is generally regarded as an important factor for other ones such as those formed in the drainage areas of the Huanghe-Huaihe Rivers and the Changjiang-Huaihe Rivers.