The use of nano-sized particles in cement system introduces a myriad of potential innovations from the new functionality to enhance both mechanical properties and durability.Preparation of such materials is energy intensive processes.Route adopted in this work to prepare Nanometric flyash particles was using newer dry milling system.The research work was carried out in a new generation High Energy Milling, HEM, system known as Simoloyer model CM 08 from Zoz GmbH, Germany for the first time in India.HEM is one of the high kinetic processing techniques in which powder material are subjected to repeated deformation by highly energetic collisions of grinding media in the mill and subsequent transfer of kinetic energy into the powder.The parameters used for grinding are variation in grinding time from 15-210 minutes keeping the grinding media/fly ash ratio constant at 8.It was expected that, If High Energy Milling (HEM) is used for the grinding of fly ash, it can lead to substantial refinement (< 1 μm) and also mechanically activate the fly ash particles.