This paper describes the incremental behaviours of Density based clustering. It specially focuses on the Density Based Spatial Clustering of Applications with Noise (DBSCAN) algorithm and its incremental approach.DBSCAN relies on a density based notion of clusters.It discovers clusters of arbitrary shapes in spatial databases with noise.In incremental approach, the DBSCAN algorithm is applied to a dynamic database where the data may be frequently updated. After insertions or deletions to the dynamic database, the clustering discovered by DBSCAN has to be updated. And we measure the new cluster by directly compute the new data entering into the existing clusters instead of rerunning the algorithm.It finally discovers new updated clusters and outliers as well.Thus it describes at what percent of delta change in the original database the actual and incremental DBSCAN algorithms behave like same.DBSCAN is widely used in those situations where large multidimensional databases are maintained such as Data Warehouse.