This research employed impervious surface analysis to examine process of urban expansion around the Hangzhou Bay, China, by integrating Landsat data obtained over two different periods between 1987 and 2009(i.e., 1987, 2001 and 2009). The amount of impervious surface was quantified by Hyper Spectral Mixture Analysis (HSMA) for each year. We developed this technique to cope with mixed pixel problem in coastal region of this Bay. Results showed that south of the Hangzhou Bay witnessed rapid impervious surface expansion(non-industrial and industrial) in the period 2001to 2009 in comparison to the north part. We found that most urban lands were connected together through developing impervious surface. As a result, it generated a large area of impervious surface along coastal of the Hangzhou Bay. This situation may induce environmental problems in this Bay.