Abstract: The benthos in the Huoxihe River were investigated in August and November of 1996.39 species of benthos were found with the density of 87.3 individuals / m2 or 0.9504mg / m2 The dominant species included Branchycentrus sp., Bactis sp., Ephemerella sp., Togoperla sp.and Antocha sp.The benthos in The Huoxihe River were typical species in the lobe water of mountain areas and their time and space distribution was in agreement.The water quality was demonstrated to be clean by the BMWP system, BBI/ FBI index and Shannon diversity index.It is suggested that the density of 70.0 individuals/m' in Branchycentrus sp.be the critical point for the clean water and the lightly-polluted water in The Huoxihe River.