T-type phase change memory has the advantages of low power consumption, non-volatility, high storage density and high reliability, so it is considered by the International Semiconductor Industry Association to be one of the mainstream products of the next generation semiconductor memory. In order to ensure the controllability of the manufacturing process of T-type phase change memory, a method for measuring three-dimensional morphology parameters of nanostructures based on optical scattering is proposed in this paper. The optical characteristic model of T-type phase change memory is established based on the rigorous coupled wave analysis method. The amplitude and phase change of elliptically polarized light on the sample to be measured are analyzed. The inverse scattering problem is used to solve the three-dimensional morphology parameters of the nanostructures to be measured. The three-dimensional morphology parameters of T-type phase change memory are measured by optical scatterometer, and the extraction results of the parameters to be measured are compared with those of scanning electron microscope. The feasibility and effectiveness of optical scatterometer in T-type phase change memory morphology characterization and manufacturing process monitoring are verified.