Field investigation and sampling analysis method was conducted to seasonal variation and vertical distribution of heavy metal chromium for Beidagang reservoir and Beitang reservoir in the coastal region of Tianjin. Results show that the content of heavy metal chromium in the reservoirs water did not exceed the standard of surface water environment quality (GB3838-2002). In different sites of reservoirs, the average level of hexavalent chromium and total chromium of reservoir water was 0.026mg/L and 0.046mg/L respectively. The average level of hexavalent chromium/total chromium of reservoir water was 68.22%, and results show that the composition of total chromium was Hexavalent chromium for reservoir water sites. Seasonal variation characteristics of heavy metal chromium in reservoir were not obviously, and showed that in winter was higher than in spring. Vertical variation characteristics of the reservoir water of heavy metal chromium underneath the surface were not obvious, and presented that heavy metal chromium increased with the increase of depth, and this result shows that heavy metal chromium of reservoirs water were derived possible from release of chromium of sediment.