By Data Grid to handle data sharing problems of distributed position in Group Purchasing. And so, evaluating and mining massive amounts of data is without fail required replication is important techniques to provide fast data access. Several replication modeling algorithms are studied in the paper. OptorSim provides a modular framework under different Grid environment. OptorSim is used to achieve the Grid simulator to research the stability and transient action. Modern group-companies are often made of many subsidiary companies. Stocking centralization can economize much fund for its large-scale purchasing action. Subordinate companies hope to choose the best provider according to reliable data in most possible area. Advanced data in variety units is massive amounts of data that must be post-processed and organized to support provider evaluation actions. Increasing data volumes from all of the companies challenge to state-of-the-art database system and data-loading techniques. Grid concept is adopted to solve the problem in the project which is named Price Comparison System (PCS). One of the key technologies in the system is to improve the data access.