Abstract: The data granularity and structure difference among the disk storage objects,memory management objects and rendering cache objects results to heavy counts of disk I/Os.This becomes one of the reasons causing data access delay.We propose a data organization method to uniform the granularity and structure in disk,memory and display cache.Firstly,we use the spatial index node from a hierarchical-nested and hybrid spatial index to uniform the disk storage,memory management and rendering cache basic operation unit.Secondly,the data structure is formated in disk and memory based on the structure of rendering cache objects.And the data layout method is extended to the object level using in disk storage to reduce the data format convention and disk I/O seeking time.Tests prove the obvious reduction of I/Os in the real-time rendering of large-scale 3D city models.