The CluStream algorithm can not process arbitrary shapes of clusters well. Having analyzed the nature of data stream, proposed the incremental clustering algorithm based on irregular grid in data stream, namely, IIGStream. IIGStream has the advantage of clustering fast which traditional grid clustering algorithms has, and it adjust the structure of grid dynamically. To new coming data points, it promises the effectiveness of clustering of different cluster shapes by judging whether the grids are connected. During the process of clustering, it need not specify the number of clusters in advance, and it is not sensitive to outliers. The experiments on real datasets and synthetic datasets show the applicability and validity of IIGStream.