In order to improve the reliability of PSA in industrial furnaces corrosion condition, tests are made in different concentration of PTFE emulsion to modify PSA fiber, and experiments are conducted on the comparison of corrosion resistance before and after modification. The results show that: the mechanics properties of PSA fiber decline after the modification with PTFE emulsion, but the corrosion resistance is obviously improved. There will be rising phenomenon of the mechanical properties of the fiber after corrosion treatment by 15% PTFE emulsion initially. The improvement of corrosion resistance of modified PSA fiber has certain relationship with the concentration of PTFE emulsion. In alkaline corrosive environment, the corrosion resistance of modified PSA fiber has a certain proportional relationship to the concentration of PTFE emulsion. In acid corrosive environment, there exists a optimal value of the concentration of PTFE emulsion. The modified effect of the concentration of 5% and 10% PTFE emulsion is better than that of 15%. This shows that the PSA must be dealt against corrosion when used in industrial furnaces with high temperature, high humidity and the corrosion condition. Dipping with PTFE emulsion is a very effective method.