The Technique of Determining Tropical Cyclone Intensity in NMC is improved according to analyses of EIR imageries (1983-1988). In the determination of the cloud index for tropical cyclone intensity, some factors are incorporated, (a) the temperature and diameter of the eye area, (b) the lowest cloud-top temperature of CDO, (c) the lowest cloud -top temperature of spiral cloud band. The relationship between cloud intensity indices and maximum wind velocity near the center of tropical cyclone is also derived from curve fitting. The new technique is more objective and quantitative than anyone before.