The spectra were measured with hand-spectral instrument in Lake Taihu, and the water samples were collected in situ and analyzed in the lab.The correlations between chlorophyll-a (CHL) and total suspended matter (TSM) and the measured spectra reflectivity were analyzed, on the basis of which, CHL and TSM concentrations were estimated by using the combination of the field bands, respectively.Then by the comparison of the bands of Landsat ETM, the most practicable ones were selected, which would be validated for the estimation of CHL and TSM content by using the Landsat ETM images.Finally, lots of regression models were discussed to educe the estimation models.Two of the most precise ones were used to estimate the CHL and TSM concentrations.The conclusion are as follows: (1) Landsat TM/ETM is one of the appropriate data resources in the multi-spectral remote sensing, but it isnt the most appropriate, (2) il is more precise lo estimate CHL content with the third band of ETM by some certain function.In addition, it is also better to estimate CHL content with the combination of ETM3 and ETM1, (3) the correlation between ETM4 and TSM is also very close, and the most precise band to estimate TSM is ETM4/ETM1, (4) the image window size has an effect on the precision to estimate the water quality parameters, and 5 by 5 or 7 by 7 is more appropriate to estimate CHL content, while 3 by 3 or less is more appropriate lo estimate TSM content.