This paper, presents an extended B-tree data structure and a series of algorithms for satisfying a new requirement of manipulating the concurrent group data at real time. By new algorithm the amount of readings and writings in the manipulation has been decreased greatly, and the efficiency of storage utilization has been increased. Discussion indicates that a database formed by the new data structure and new algorithm has the advantages of a lower tree height, a better efficiency of page utilization, and a little cost of operating overhead as compared to a database formed by B-tree and general algorithm.