The invention discloses an analysis method of ammonio-carboxymethyl cellulose substitution degree, and belongs to the field of analytical testing. The technical purpose is to provide a new analysis method of ammonio-carboxymethyl cellulose substitution degree. According to the method, ammonio-carboxymethyl cellulose is decomposed in the catalytic heating condition, produced ammonia reacts with sulfuric acid to produce ammonium sulfate, alkalifying distillation is conducted to make ammonia free, the free ammonia is absorbed by boric acid, then titrating is conducted with sulfuric acid standardvolumetric solution, the millimole number of carboxymethyl groups contained by per gram of ammonio-carboxymethyl cellulose is obtained by calculation based on the consumption amount of the acid, and the substitution degree of ammonio-carboxymethyl cellulose is further obtained; analysis results are stable and reliable, regulation of the production technology of the ammonio-carboxymethyl celluloseproduct can be guided, and thus the quality of the ammonio-carboxymethyl cellulose product is improved.