Effect of sulfuric acid as catalyst due to synthesis of nitrocellulose from pure cellulose towards substitusion degree had been done. The purpose of this research are to find FT-IR absorbance and substitution degree. Nitrocellulose wassynthesized using nitration method in a mixture nitric acid, sulfuric acid and water then cooled at 5OC - 15OC for 60 minutes. Results is showed that nitrocellulose synthesized has FT-IR character that the formation nitro functional group (-NO2) sharp peak at 1635 cm-1 were subtituted completely. However the peak at 1361 cm-1 and 1288 cm-1 nitro functional group (-NO2) incompletely substituted because peak is not sharp. So two hydroxyl functional group peak (-OH) at 3201 cm-1 and 3424 cm-1. Concluded, substitution degree using absorbance ratio from FT-IR spectrum is 2,89.