The invention discloses a purification method for beta-nicotinamide mononucleotide. The method comprises the steps of: a. carrying out microfiltration and nanofiltration on a pretreated beta-nicotinamide mononucleotide solution by membrane concentration equipment, and collecting the concentrated crude product solution; b. adjusting the pH value of the obtained crude product solution to 3-7, performing sample introduction and loading the sample on a reversed-phase high performance liquid chromatogram preparation column, taking octadecyl silane bonded silica gel as the stationary phase, taking a hydrochloric acid solution prepared solution with pH of 3-7 as the mobile phase A and ethanol as the mobile phase, carrying out gradient elution and purification so as to obtain a purified sample solution; and c. carrying out nanofiltration on the purified sample solution by the membrane concentration equipment, then conducting freeze-drying by a vacuum freeze dryer, thus obtaining purified beta-nicotinamide mononucleotide.