Sodium carboxymethyl cellulose (Na-CMC) is commonly used an excipient on pharmaceutical product. Kapok fiber is one of natural material that contains high amount of cellulose ranges from 35% - 64%. The present research aimed to find out the optimum condition and method of NaCMC prepared from α-cellulose kapok fiber and its identity and characteristics compared to commercial NaCMC. Alkalization was carried out using 25% sodium hydroxide and 1.7% sodium tetraborate. The carboxymethylation reaction was optimized by variation of weight of sodium monochloroacetate (NaMCA) and duration of reaction. The degree of substitution (DS) was determined by acid-base titration method. The optimum NaCMC product with DS value of 0.72 was obtained from carboxymethylation reaction with sodium monochloroacetate to alpha cellulose ratio 1.25 : 1. The NaCMC was obtained in the form of fine powder, odourless, tasteless, white and the pH value of 1% solution was 7.14. The infrared spectra of NaCMC was similar to commercial reference. Based on the comparison of diffractogram by X-Ray diffraction, there was a similarity pattern between NaCMC of kapok fiber with the reference which showed crystalline and amorphous form. Morphologically by using SEM (Scanning Electron Microscope), it showed a more flat and coarser morphological shape than the commercial reference. Overall, NaCMC from kapok fiber alpha cellulose similar with the commercial NaCMC.