Abstract: The degradation effects of paraffin by paraffin-thirsty bacteria PWⅠ under the concentrations of different salt concentration, culture media and trace elements were studied. The results showed that the degradation rate of paraffin by paraffin-thirsty bacteria PWⅠreached the maximum （47.31%） when salt concentration was 1%. And the degradation rate of paraffin in liquid culture medium of paraffin was 47.76%. Different trace elements had obvious effects on the degradation of paraffin. The degradation rates of paraffin when Cu2＋concentration, Zn2＋concentration and Fe2＋concentration were 0.10, 0.07 and 0.55μmol/L respectively reached the maximum values, being 48.30%, 47.95% and 45.26% respectively. These results will be helpful for applying PWⅠin paraffin removal and control of oil well in biological technology and enhancing the oil productivity of oil well.