Abstract: In order to study the effect of alkaline pectinase scouring of cotton knitted fabric easily, the paper has demonstrated the practicability of analysis of the scouring effect of cotton knitted fabric with alkaline pectinase by FT-IR attenuated total reflectance spectroscopy (FT-IR ATR). Tests show that cotton knitted fabric treated by hydrochloric acid vapor can be assessed by FT-IR ATR spectroscopy for the effect of scouring. Finally, this paper compared the effect of alkali scouring with that of alkaline pectinase scouring. FT-IR ATR spectra shows that good effect of scouring of cotton knitted fabric is achieved with alkaline pectinase, which is close to that of alkali scouring. The paper provides a new way to assess the effect of alkaline pectinase scouring of cotton knitted fabric.