Odor compounds 2-methylisocrotene (MIB) and the geosmin (Geo) were highly overlapped with the water blooms in the Lake Taihu. In this study, the relationship between odor compounds and cyanobacterial or algal strains of blooms in Lake Taihu were investigated by analyzing laboratory cultures and field samples. The cultured strains included 15 cyanobacteria (11 Microcystis strains),4 green algae and 4 diatoms. No MIB was detected in all strains, and Geo was only detected in the culture of diatoms. Analysis of field water samples showed that the concentration of Microcystis cells was not correlated with the concentration of MIB and Geo. Decay of Microcysits bloom did not produced MIB and Geo in either aerobic or anaerobic conditions. These data demonstrated that MIB and Geo were not directly related to Microcystis, dominant population of bloom. A high concentration of MIB was found in an Anabaena bloom. Data analysis of annual water samples showed that the cell density of Anabaena was consistent with the change of MIB concentration, which suggested Anabaena should be an important producer of MIB. However, the Anabaena PCC 7120 cultured in laboratory did not produced MIB and Geo both in the culture medium with nitrate or without nitrogen. The result implied that the production of odor substances was of strain specificity.