北京正负电子对撞机重大改造工程(BEPCII)已建成并通过验收，升级后的北京谱仪III (BESIII)获取的原始数据正快速累积。通过BESIII离线软件系统(BOSS)将原始数据进行重建并产生相应的模拟数据，是开展BESIII物理分析的基础。随着数据量的增大，某些高优先级的数据处理任务耗时过长，使后续任务长时间等待，导致数据处理周期越来越长，CPU资源不能得到充分利用，物理分析工作不能及时展开。此外，数据量的快速增大使磁盘空间日益紧张，采用现有的数据访问方式，不仅造成磁盘空间的严重浪费，也限制了数据处理和物理分析的速度。本项目旨在开发一种新的事例级分布式软件系统，大幅提高离线数据处理的速度，缩短数据处理周期；同时，研究通过事例索引实现高效的事例导航，大幅节约磁盘空间，提高数据处理和物理分析的速度。本项目的顺利实施将帮助BESIII实验更快更好的取得物理成果。

BEPCII has been constructed and passed the acceptance. The upgraded detector BESIII accumulates massive raw data rapidly. The reconstruction of raw data and the following generation of Monte Carlo simulation data with BESIII Offline Software System (BOSS) are the basis of BESIII physics analysis. With the increase of data volume, the time consuming of some high priority data processing jobs causes overlong suspending of the succeeding jobs and inefficiently usage of CPU resources. The increased data processing cycle hinders the promptly carrying out of physics analysis work. In addition, the current data accessing module wastes disk space seriously and restricts the speed of data processing and physics analysis jobs while disk space becomes tight with data volume growth. This project aims to develop a new event-level distributed system which improves data processing speed and reduces data processing cycle, and an event index navigation system which saving disk space and speeding up data processing and physics analysis. The implementation of this project helps to achieve important physics results on BESIII experiment faster and better.