Objective To explore the organic and biological contamination in water body of Jin River of Tianjin. Methods Three sections were set up in the upper reaches, middle reaches and lower reaches of Jin River respectively. 6 sampling points were set up in each section of the river. The levels of BOD_5~(20), total count of bacteria, fecal coliform count of the river water were determined. The obtained data were assessed based on GB3838-2002 the National Criterion for Environmental Quality of Surface Water. Results The levels of BOD_5~(20) of river water samples collected from each section of Jin River exceeded the standard ruled by GB3838-2002 Grade V. The levels of fecal coliform count of water samples were between the national standards of Grade Ⅲ and Ⅴ of GB3838-2002. The water samples collected from different sections of Jin River water showed no significant differences in the levels of BOD_5~(20) and fecal coliform count, and significant difference in total count of bacteria. Significantly higher levels of total count of bacteria were observed in water samples collected from upper reaches of Jin River compared with those collected from lower reaches (P