Terephthalic acid is one of the main contaminations released by PET processing and it's toxic to environment and animals. Useful microbe must be found out to biodegrade it. Bacillus came from waste water may be powerful to biodegrade it, so the waste water were used as the sources of bacillus. The microbe was enriched in enrichment medium first and then isolated on selective medium containing terephthalic acid as the only carbon source to get the microbe suitable for degradation. The purified microbe was used to biodegrade terephthalic acid at different temperature to find out its suitable living and degradation condition. The microbe was identified with molecule biological identification and biolog express identification. The fermentation condition of the purified microbe was studied. The enzyme activity, growth condition and degradation condition was studied. The results showed that the isolated microbe was a kind of bacillus named comamonas testosteroni. It's powerful to degrade terephthalic acid at 37 °C with the rotational speed of 200 rpm. The pH of the medium would increase during degradation of substrate. The degradation would consumed a lot of oxygen. A degradation path may be deduced.